Remove double subject call in `services/suspend_account_service` spec (#28213)

spec/services/suspend_account_service_spec.rb

@@ -18,14 +18,15 @@ RSpec.describe SuspendAccountService, type: :service do
       account.suspend!
     end
 
-    it "unmerges from local followers' feeds" do
-      subject
+    it 'unmerges from feeds of local followers and preserves suspended flag' do
+      expect { subject }
+        .to_not change_suspended_flag
       expect(FeedManager.instance).to have_received(:unmerge_from_home).with(account, local_follower)
       expect(FeedManager.instance).to have_received(:unmerge_from_list).with(account, list)
     end
 
-    it 'does not change the “suspended” flag' do
-      expect { subject }.to_not change(account, :suspended?)
+    def change_suspended_flag
+      change(account, :suspended?)
     end
   end