[release/7.0] Remove experimental and downlevel feeds (#44879)

- [release/7.0] Remove experimental and downlevel feeds
- Change additional versions
  - bump SiteExtension.3.1 and SiteExtension.6.0 package versions
  - downgrade Microsoft.Extensions.DiagnosticAdapter to avoid needing the dotnet5 feed

NuGet.config

@@ -14,14 +14,11 @@
     <add key="dotnet-tools" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-tools/nuget/v3/index.json" />
     <add key="dotnet7" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet7/nuget/v3/index.json" />
     <add key="dotnet7-transport" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet7-transport/nuget/v3/index.json" />
-    <add key="dotnet6" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet6/nuget/v3/index.json" />
-    <add key="dotnet6-transport" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet6-transport/nuget/v3/index.json" />
-    <add key="dotnet5" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet5/nuget/v3/index.json" />
-    <add key="dotnet5-transport" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet5-transport/nuget/v3/index.json" />
-    <add key="dotnet-experimental" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-experimental/nuget/v3/index.json" />
     <add key="dotnet-public" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-public/nuget/v3/index.json" />
-    <!-- Used for the SiteExtension 3.1 bits that are included in the 5.0 build -->
+    <!-- Used for the SiteExtension bits that are included in the 7.0 build -->
     <add key="dotnet31-transport" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet3.1-transport/nuget/v3/index.json" />
+    <add key="dotnet5-transport" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet5-transport/nuget/v3/index.json" />
+    <add key="dotnet6-transport" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet6-transport/nuget/v3/index.json" />
     <!-- Used for the Rich Navigation indexing task -->
     <add key="richnav" value="https://pkgs.dev.azure.com/azure-public/vside/_packaging/vs-buildservices/nuget/v3/index.json" />
   </packageSources>

eng/Versions.props

@@ -161,8 +161,9 @@
     <!-- Bumping the Roslyn version used in order to ingest the new runtime source generators -->
     <UsingToolMicrosoftNetCompilers>true</UsingToolMicrosoftNetCompilers>
     <MicrosoftNetCompilersToolsetVersion>4.4.0-3.22452.8</MicrosoftNetCompilersToolsetVersion>
-    <!-- DiagnosticAdapter package pinned temporarily until migrated/deprecated -->
-    <MicrosoftExtensionsDiagnosticAdapterVersion>5.0.0-preview.4.20180.4</MicrosoftExtensionsDiagnosticAdapterVersion>
+    <!-- DiagnosticAdapter package pinned temporarily (??) until migrated/deprecated -->
+    <!-- This is the latest version found in dotnet-public. -->
+    <MicrosoftExtensionsDiagnosticAdapterVersion>5.0.0-preview.3.20215.2</MicrosoftExtensionsDiagnosticAdapterVersion>
     <!-- Build tool dependencies -->
     <MicrosoftVSSDKBuildToolsVersion>15.9.3032</MicrosoftVSSDKBuildToolsVersion>
     <!-- Stable dotnet/corefx packages no longer updated for .NET Core 3 -->
@@ -228,16 +229,16 @@
     <SystemComponentModelAnnotationsVersion>5.0.0</SystemComponentModelAnnotationsVersion>
     <SystemNetExperimentalMsQuicVersion>5.0.0-alpha.20560.6</SystemNetExperimentalMsQuicVersion>
     <SystemSecurityPrincipalWindowsVersion>5.0.0</SystemSecurityPrincipalWindowsVersion>
-    <!-- Packages from 2.1, 3.1, and 5.0 branches used for site extension build. -->
+    <!-- Packages from downlevel branches used for site extension build. -->
     <MicrosoftAspNetCoreAzureAppServicesSiteExtension21Version>2.1.1</MicrosoftAspNetCoreAzureAppServicesSiteExtension21Version>
     <MicrosoftAspNetCoreAzureAppServicesSiteExtension22Version>2.2.0</MicrosoftAspNetCoreAzureAppServicesSiteExtension22Version>
-    <MicrosoftAspNetCoreAzureAppServicesSiteExtension31Version>3.1.28-servicing-22364-2</MicrosoftAspNetCoreAzureAppServicesSiteExtension31Version>
+    <MicrosoftAspNetCoreAzureAppServicesSiteExtension31Version>3.1.30-servicing-22476-24</MicrosoftAspNetCoreAzureAppServicesSiteExtension31Version>
     <MicrosoftAspNetCoreAzureAppServicesSiteExtension31x64Version>$(MicrosoftAspNetCoreAzureAppServicesSiteExtension31Version)</MicrosoftAspNetCoreAzureAppServicesSiteExtension31x64Version>
     <MicrosoftAspNetCoreAzureAppServicesSiteExtension31x86Version>$(MicrosoftAspNetCoreAzureAppServicesSiteExtension31Version)</MicrosoftAspNetCoreAzureAppServicesSiteExtension31x86Version>
     <MicrosoftAspNetCoreAzureAppServicesSiteExtension50Version>5.0.17-servicing-22215-7</MicrosoftAspNetCoreAzureAppServicesSiteExtension50Version>
     <MicrosoftAspNetCoreAzureAppServicesSiteExtension50x64Version>$(MicrosoftAspNetCoreAzureAppServicesSiteExtension50Version)</MicrosoftAspNetCoreAzureAppServicesSiteExtension50x64Version>
     <MicrosoftAspNetCoreAzureAppServicesSiteExtension50x86Version>$(MicrosoftAspNetCoreAzureAppServicesSiteExtension50Version)</MicrosoftAspNetCoreAzureAppServicesSiteExtension50x86Version>
-    <MicrosoftAspNetCoreAzureAppServicesSiteExtension60Version>6.0.8-servicing-22363-16</MicrosoftAspNetCoreAzureAppServicesSiteExtension60Version>
+    <MicrosoftAspNetCoreAzureAppServicesSiteExtension60Version>6.0.10-servicing-22476-17</MicrosoftAspNetCoreAzureAppServicesSiteExtension60Version>
     <MicrosoftAspNetCoreAzureAppServicesSiteExtension60x64Version>$(MicrosoftAspNetCoreAzureAppServicesSiteExtension60Version)</MicrosoftAspNetCoreAzureAppServicesSiteExtension60x64Version>
     <MicrosoftAspNetCoreAzureAppServicesSiteExtension60x86Version>$(MicrosoftAspNetCoreAzureAppServicesSiteExtension60Version)</MicrosoftAspNetCoreAzureAppServicesSiteExtension60x86Version>
     <!-- 3rd party dependencies -->