Backend changes to allow setting dashboard timezone

app/models/project_metrics_setting.rb

@@ -9,4 +9,8 @@ class ProjectMetricsSetting < ApplicationRecord
     addressable_url: { enforce_sanitization: true, ascii_only: true }
 
   enum dashboard_timezone: { local: 0, utc: 1 }
+
+  def dashboard_timezone=(val)
+    super(val&.downcase)
+  end
 end

app/views/projects/settings/operations/_metrics_dashboard.html.haml

 .js-operation-settings{ data: { operations_settings_endpoint: project_settings_operations_path(@project),
   help_page: help_page_path('user/project/integrations/prometheus'),
   external_dashboard: { url: metrics_external_dashboard_url,
-    help_page: help_page_path('user/project/operations/linking_to_an_external_dashboard'),
-  } } }
+    help_page: help_page_path('user/project/operations/linking_to_an_external_dashboard') },
+  dashboard_timezone: { setting: metrics_dashboard_timezone.upcase } } }

spec/models/project_metrics_setting_spec.rb

@@ -52,4 +52,12 @@ describe ProjectMetricsSetting do
       end
     end
   end
+
+  describe '#dashboard_timezone=' do
+    it 'downcases string' do
+      subject.dashboard_timezone = 'UTC'
+
+      expect(subject.dashboard_timezone).to eq('utc')
+    end
+  end
 end