Removes feature flag ipynbdiff_notes_tracker

Feature has been active for many milestones, no need to keep this live.

Changelog: other

app/services/notes/create_service.rb

@@ -212,7 +212,7 @@ def track_note_creation_usage_for_merge_requests(note)
     end
 
     def should_track_ipynb_notes?(note)
-      Feature.enabled?(:ipynbdiff_notes_tracker) && note.respond_to?(:diff_file) && note.diff_file&.ipynb?
+      note.respond_to?(:diff_file) && note.diff_file&.ipynb?
     end
 
     def track_note_creation_in_ipynb(note)

config/feature_flags/development/ipynbdiff_notes_tracker.yml

----
-name: ipynbdiff_notes_tracker
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/85398
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/362232
-milestone: '15.0'
-type: development
-group: group::incubation
-default_enabled: false

spec/services/notes/create_service_spec.rb

@@ -395,27 +395,12 @@
             context 'is ipynb file' do
               before do
                 allow_any_instance_of(::Gitlab::Diff::File).to receive(:ipynb?).and_return(true)
-                stub_feature_flags(ipynbdiff_notes_tracker: false)
               end
 
-              context ':ipynbdiff_notes_tracker is off' do
-                it 'does not track ipynb note usage data' do
-                  expect(::Gitlab::UsageDataCounters::IpynbDiffActivityCounter).not_to receive(:note_created)
+              it 'tracks ipynb diff note creation' do
+                expect(::Gitlab::UsageDataCounters::IpynbDiffActivityCounter).to receive(:note_created)
 
-                  described_class.new(project_with_repo, user, new_opts).execute
-                end
-              end
-
-              context ':ipynbdiff_notes_tracker is on' do
-                before do
-                  stub_feature_flags(ipynbdiff_notes_tracker: true)
-                end
-
-                it 'tracks ipynb diff note creation' do
-                  expect(::Gitlab::UsageDataCounters::IpynbDiffActivityCounter).to receive(:note_created)
-
-                  described_class.new(project_with_repo, user, new_opts).execute
-                end
+                described_class.new(project_with_repo, user, new_opts).execute
               end
             end
           end