Use an uncached application setting for usage ping checks

The introduction of the in-memory cache for application settings had a
side effect of making it harder to invalidate changes when the settings
occur. We now bypass the cache because it's possible the admin enabled
the usage ping, and we don't want to annoy the user again if they
already set the value.

To avoid causing significant load on the system, we add an extra check
to ensure the user is an admin. and we don't want to annoy the user
again if they already set the value. This is a bit of hack, but the
alternative would be to put in a more complex cache invalidation
step. Since this call only gets called in the uncommon situation where
the user is an admin and the only user in the instance, this shouldn't
cause too much load on the system.

app/models/user.rb

@@ -1460,7 +1460,7 @@ class User < ApplicationRecord
   end
 
   def requires_usage_stats_consent?
-    !consented_usage_stats? && 7.days.ago > self.created_at && !has_current_license? && User.single_user?
+    self.admin? && 7.days.ago > self.created_at && !has_current_license? && User.single_user? && !consented_usage_stats?
   end
 
   # Avoid migrations only building user preference object when needed.
@@ -1495,7 +1495,14 @@ class User < ApplicationRecord
   end
 
   def consented_usage_stats?
-    Gitlab::CurrentSettings.usage_stats_set_by_user_id == self.id
+    # Bypass the cache here because it's possible the admin enabled the
+    # usage ping, and we don't want to annoy the user again if they
+    # already set the value. This is a bit of hack, but the alternative
+    # would be to put in a more complex cache invalidation step. Since
+    # this call only gets called in the uncommon situation where the
+    # user is an admin and the only user in the instance, this shouldn't
+    # cause too much load on the system.
+    ApplicationSetting.current_without_cache&.usage_stats_set_by_user_id == self.id
   end
 
   # Added according to https://github.com/plataformatec/devise/blob/7df57d5081f9884849ca15e4fde179ef164a575f/README.md#activejob-integration

spec/models/user_spec.rb

@@ -3354,7 +3354,7 @@ describe User do
   end
 
   describe '#requires_usage_stats_consent?' do
-    let(:user) { create(:user, created_at: 8.days.ago) }
+    let(:user) { create(:user, :admin, created_at: 8.days.ago) }
 
     before do
       allow(user).to receive(:has_current_license?).and_return false