Move subscription locales into controller scope

config/locales/controllers.en.yml

@@ -196,6 +196,13 @@ en:
           error: :errors.invalid_otp
         destroy:
           success: "Two factor authentication has been disabled for your account."
+  subscriptions:
+    create:
+      success: "Successfully subscribed."
+      error: "Failed to subscribe to answer."
+    destroy:
+      success: "Successfully unsubscribed."
+      error: "Failed to unsubscribe from answer."
   user:
     sessions:
       create:

config/locales/frontend.en.yml

@@ -6,12 +6,6 @@ en:
     error:
       title: "Uh-oh…"
       message: "An error occurred, a developer should check the console for details"
-    subscription:
-      subscribe: "Successfully subscribed."
-      unsubscribe: "Successfully unsubscribed."
-      fail:
-        subscribe: "Failed to subscribe to answer."
-        unsubscribe: "Failed to unsubscribe from answer."
     list:
       confirm:
         title: "Are you sure?"