Remove the `incident_metric_upload_ui` feature flag

ee/app/models/issuable_metric_image.rb

@@ -21,7 +21,7 @@ class IssuableMetricImage < ApplicationRecord
   MAX_FILE_SIZE = 1.megabyte.freeze
 
   def self.available_for?(project)
-    Feature.enabled?(:incident_metric_upload_ui, project) && project&.feature_available?(:incident_metric_upload)
+    project&.feature_available?(:incident_metric_upload)
   end
 
   def filename

ee/changelogs/unreleased/tr-metric-image-feature-flag-removal.yml

+---
+title: Add metric image feature for Incidents
+merge_request: 51552
+author:
+type: added

ee/config/feature_flags/development/incident_metric_upload_ui.yml

----
-name: incident_metric_upload_ui
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/46731
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/293934
-milestone: '13.8'
-type: development
-group: group::monitor
-default_enabled: false

ee/spec/helpers/ee/issuables_helper_spec.rb

@@ -84,7 +84,6 @@ RSpec.describe IssuablesHelper do
       context 'when incident metric upload is available' do
         before do
           stub_licensed_features(incident_metric_upload: true)
-          stub_feature_flags(incident_metric_upload_ui: issue.project)
         end
 
         let_it_be(:issue) { create(:issue, author: user, description: 'issue text', issue_type: :incident) }

ee/spec/models/issuable_metric_image_spec.rb

@@ -44,23 +44,14 @@ RSpec.describe IssuableMetricImage do
 
     before do
       stub_licensed_features(incident_metric_upload: true)
-      stub_feature_flags(incident_metric_upload_ui: true)
     end
 
     let_it_be_with_refind(:issue) { create(:issue) }
 
-    context 'license and feature flag enabled' do
+    context 'license enabled' do
       it { is_expected.to eq(true) }
     end
 
-    context 'feature flag disabled' do
-      before do
-        stub_feature_flags(incident_metric_upload_ui: false)
-      end
-
-      it { is_expected.to eq(false) }
-    end
-
     context 'license disabled' do
       before do
         stub_licensed_features(incident_metric_upload: false)