Remove not existing feature flag from tests

Tests for `EE::SubscribableBannerHelper` were testing against feature
flag that do not exists (`subscribable_banner`). Remove this flag from
tests, and add some tests for when `subscribable_subscription_banner` is
enabled/disabled.

See https://gitlab.com/gitlab-org/gitlab/-/issues/295308.

ee/spec/helpers/ee/subscribable_banner_helper_spec.rb

@@ -16,60 +16,42 @@ RSpec.describe EE::SubscribableBannerHelper do
       end
     end
 
-    context 'when feature flag is enabled' do
-      let(:license) { double(:license) }
+    let(:license) { double(:license) }
 
+    context 'when instance variable true' do
       before do
-        stub_feature_flags(subscribable_banner: true)
+        assign(:display_subscription_banner, true)
       end
 
-      context 'when instance variable true' do
+      context 'when should_check_namespace_plan is true' do
         before do
-          assign(:display_subscription_banner, true)
+          allow(::Gitlab::CurrentSettings).to receive(:should_check_namespace_plan?).and_return(true)
         end
 
-        context 'when should_check_namespace_plan is true' do
-          before do
-            allow(::Gitlab::CurrentSettings).to receive(:should_check_namespace_plan?).and_return(true)
-          end
-
-          context 'when a project exists' do
-            let(:entity) { create(:project) }
-
-            before do
-              assign(:project, entity)
-            end
+        context 'when a project exists' do
+          let(:entity) { create(:project) }
 
-            it_behaves_like 'when a subscription exists'
+          before do
+            assign(:project, entity)
           end
 
-          context 'when a group exists' do
-            let(:entity) { create(:group) }
-
-            before do
-              assign(:group, entity)
-            end
-
-            it_behaves_like 'when a subscription exists'
-          end
+          it_behaves_like 'when a subscription exists'
         end
 
-        context 'when should_check_namespace_plan is false' do
+        context 'when a group exists' do
+          let(:entity) { create(:group) }
+
           before do
-            allow(::Gitlab::CurrentSettings).to receive(:should_check_namespace_plan?).and_return(false)
+            assign(:group, entity)
           end
 
-          it 'returns the current license' do
-            expect(License).to receive(:current).and_return(license)
-            expect(subject).to eq(license)
-          end
+          it_behaves_like 'when a subscription exists'
         end
       end
 
-      context 'when instance variable false' do
+      context 'when should_check_namespace_plan is false' do
         before do
-          assign(:display_subscription_banner, false)
-          allow(::Gitlab::CurrentSettings).to receive(:should_check_namespace_plan?).and_return(true)
+          allow(::Gitlab::CurrentSettings).to receive(:should_check_namespace_plan?).and_return(false)
         end
 
         it 'returns the current license' do
@@ -77,18 +59,30 @@ RSpec.describe EE::SubscribableBannerHelper do
           expect(subject).to eq(license)
         end
       end
+    end
 
-      context 'with a future dated license' do
-        let(:gl_license) { build(:gitlab_license, starts_at: Date.current + 1.month) }
+    context 'when instance variable false' do
+      before do
+        assign(:display_subscription_banner, false)
+        allow(::Gitlab::CurrentSettings).to receive(:should_check_namespace_plan?).and_return(true)
+      end
 
-        before do
-          allow(::Gitlab::CurrentSettings).to receive(:should_check_namespace_plan?).and_return(true)
-        end
+      it 'returns the current license' do
+        expect(License).to receive(:current).and_return(license)
+        expect(subject).to eq(license)
+      end
+    end
 
-        it 'returns the current license' do
-          allow(License).to receive(:current).and_return(license)
-          expect(subject).to eq(license)
-        end
+    context 'with a future dated license' do
+      let(:gl_license) { build(:gitlab_license, starts_at: Date.current + 1.month) }
+
+      before do
+        allow(::Gitlab::CurrentSettings).to receive(:should_check_namespace_plan?).and_return(true)
+      end
+
+      it 'returns the current license' do
+        allow(License).to receive(:current).and_return(license)
+        expect(subject).to eq(license)
       end
     end
   end
@@ -98,9 +92,9 @@ RSpec.describe EE::SubscribableBannerHelper do
 
     let(:message) { double(:message) }
 
-    context 'when feature flag is enabled' do
+    context 'when subscribable_subscription_banner feature flag is enabled' do
       before do
-        stub_feature_flags(subscribable_banner: true)
+        stub_feature_flags(subscribable_subscription_banner: true)
       end
 
       context 'when instance variable true' do
@@ -201,6 +195,19 @@ RSpec.describe EE::SubscribableBannerHelper do
         end
       end
     end
+
+    context 'when subscribable_subscription_banner feature flag is disabled' do
+      before do
+        stub_feature_flags(subscribable_subscription_banner: false)
+        assign(:display_subscription_banner, true)
+        allow(::Gitlab::CurrentSettings).to receive(:should_check_namespace_plan?).and_return(true)
+      end
+
+      it 'returns the license message' do
+        expect(helper).to receive(:license_message).and_return(message)
+        expect(subject).to eq(message)
+      end
+    end
   end
 
   describe '#display_subscription_banner!' do