Merge branch 'remove-unnecessary-freeze-in-app-helpers' into 'master'

Avoid calling freeze on already frozen strings in app/helpers

See merge request gitlab-org/gitlab-ce!32789

app/helpers/user_callouts_helper.rb

 # frozen_string_literal: true
 
 module UserCalloutsHelper
-  GKE_CLUSTER_INTEGRATION = 'gke_cluster_integration'.freeze
-  GCP_SIGNUP_OFFER = 'gcp_signup_offer'.freeze
-  SUGGEST_POPOVER_DISMISSED = 'suggest_popover_dismissed'.freeze
+  GKE_CLUSTER_INTEGRATION = 'gke_cluster_integration'
+  GCP_SIGNUP_OFFER = 'gcp_signup_offer'
+  SUGGEST_POPOVER_DISMISSED = 'suggest_popover_dismissed'
 
   def show_gke_cluster_integration_callout?(project)
     can?(current_user, :create_cluster, project) &&