[Rails5] Fix error on missed :authenticate_user callback

Since 5.0 Rails by default now raises the ArgumentError if an unrecognized
callback is skipped. [1]

This commit adds `raise: false` to act as rails 4.

[1]: https://github.com/rails/rails/commit/d2876141d08341ec67cf6a11a073d1acfb920de7

ee/app/controllers/projects/vulnerability_feedback_controller.rb

@@ -2,7 +2,7 @@ class Projects::VulnerabilityFeedbackController < Projects::ApplicationControlle
   before_action :vulnerability_feedback, only: [:destroy]
   before_action :authorize_read_vulnerability_feedback!, only: [:index]
   before_action :authorize_admin_vulnerability_feedback!, only: [:create, :destroy]
-  skip_before_action :authenticate_user!, only: [:index]
+  skip_before_action :authenticate_user!, only: [:index], raise: false
 
   respond_to :json
 

ee/app/controllers/unsubscribes_controller.rb

 class UnsubscribesController < ApplicationController
   skip_before_action :authenticate_user!,
                      :reject_blocked, :set_current_user_for_observers,
-                     :add_abilities
+                     :add_abilities, raise: false
 
   def show
     @user = get_user

ee/changelogs/unreleased/blackst0ne-rails5-argumenterror-before-process_action-callback-reject_blocked-has-not-been-defined.yml

+---
+title: "[Rails5] Fix error on missed :authenticate_user callback"
+merge_request: 6257
+author: "@blackst0ne"
+type: fixed