Collect metrics from all pull mirrors

Contributes to #367846

**Problem**

`def mirror?` includes additional checks that can exclude processing of
projects with pull mirroring enabled but without the license to use it.

**Solution**

Fetch `mirror` status directly from the project.

Changelog: changed
EE: true

ee/app/models/ee/project_import_state.rb

@@ -90,13 +90,13 @@ def in_progress?
     end
 
     def mirror_waiting_duration
-      return unless mirror?
+      return unless project.read_attribute('mirror')
 
       (last_update_started_at.to_i - last_update_scheduled_at.to_i).seconds
     end
 
     def mirror_update_duration
-      return unless mirror?
+      return unless project.read_attribute('mirror')
 
       (last_update_at.to_i - last_update_started_at.to_i).seconds
     end

ee/spec/models/project_import_state_spec.rb

@@ -213,35 +213,59 @@
   end
 
   describe '#mirror_waiting_duration' do
-    it 'returns nil if not mirror' do
-      import_state = create(:import_state, :scheduled)
-
-      expect(import_state.mirror_waiting_duration).to be_nil
-    end
+    let(:import_state) { create(:import_state, :scheduled, :mirror) }
 
     it 'returns in seconds the time spent in the queue' do
-      import_state = create(:import_state, :scheduled, :mirror)
-
       import_state.last_update_started_at = import_state.last_update_scheduled_at + 5.minutes
 
       expect(import_state.mirror_waiting_duration).to eq(300)
     end
-  end
 
-  describe '#mirror_update_duration' do
-    it 'returns nil if not mirror' do
-      import_state = create(:import_state, :started)
+    context 'when account does not have a license' do
+      before do
+        stub_licensed_features(repository_mirrors: false)
+      end
 
-      expect(import_state.mirror_update_duration).to be_nil
+      it 'returns in seconds the time spent in the queue' do
+        import_state.last_update_started_at = import_state.last_update_scheduled_at + 1.minute
+
+        expect(import_state.mirror_waiting_duration).to eq(60)
+      end
     end
 
-    it 'returns in seconds the time spent updating' do
-      import_state = create(:import_state, :started, :mirror)
+    context 'when import state is not mirror' do
+      let(:import_state) { create(:import_state, :scheduled) }
+
+      it { expect(import_state.mirror_waiting_duration).to be_nil }
+    end
+  end
 
+  describe '#mirror_update_duration' do
+    let(:import_state) { create(:import_state, :started, :mirror) }
+
+    it 'returns in seconds the time spent updating' do
       import_state.last_update_at = import_state.last_update_started_at + 5.minutes
 
       expect(import_state.mirror_update_duration).to eq(300)
     end
+
+    context 'when account does not have a license' do
+      before do
+        stub_licensed_features(repository_mirrors: false)
+      end
+
+      it 'returns in seconds the time spent in the queue' do
+        import_state.last_update_at = import_state.last_update_started_at + 1.minute
+
+        expect(import_state.mirror_update_duration).to eq(60)
+      end
+    end
+
+    context 'when import state is not mirror' do
+      let(:import_state) { create(:import_state, :scheduled) }
+
+      it { expect(import_state.mirror_update_duration).to be_nil }
+    end
   end
 
   describe '#updating_mirror?' do