Resolve "metric fo sync with GitLab License DB by package type"

config/metrics/objects_schemas/package_registry_metadata_sync_activation_by_type_metric.json

+{
+  "type": "array",
+  "items": {
+    "type": [
+      "string"
+    ]
+  }
+}

ee/config/metrics/settings/20240229135438_package_metadata_sync_activation_by_type_metric.yml

+---
+key_path: settings.package_metadata_sync_activation_by_type_metric
+description: "List the package types that have sync enabled to registries"
+product_section: sec
+product_stage: secure
+product_group: composition_analysis
+value_type: object
+status: active
+milestone: "17.0"
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/146176
+time_frame: none
+data_source: system
+data_category: optional
+instrumentation_class: PackageRegistryMetadataSyncActivationByTypeMetric
+performance_indicator_type: []
+distribution:
+- ee
+tier:
+- ultimate
+value_json_schema: "config/metrics/objects_schemas/package_registry_metadata_sync_activation_by_type_metric.json"

ee/lib/gitlab/usage/metrics/instrumentations/package_registry_metadata_sync_activation_by_type_metric.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Usage
+    module Metrics
+      module Instrumentations
+        class PackageRegistryMetadataSyncActivationByTypeMetric < GenericMetric
+          def value
+            ::PackageMetadata::SyncConfiguration.permitted_purl_types
+          end
+        end
+      end
+    end
+  end
+end

ee/spec/lib/gitlab/usage/metrics/instrumentations/package_registry_metadata_sync_activation_by_type_metric_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Usage::Metrics::Instrumentations::PackageRegistryMetadataSyncActivationByTypeMetric, feature_category: :software_composition_analysis do
+  let(:expected_value) { PackageMetadata::SyncConfiguration.permitted_purl_types }
+  let(:expected_query) { expected_value }
+
+  it_behaves_like 'a correct instrumented metric value and query', { time_frame: 'all' }
+end