Release jira_connect_proxy_create_branch

This removes the :jira_connect_proxy_create_branch feature flag as the feature has been globally enabled on production for a week with no issues.

Changelog: fixed

app/controllers/jira_connect/branches_controller.rb

 # frozen_string_literal: true
 
 class JiraConnect::BranchesController < JiraConnect::ApplicationController
-  # before_action :authenticate_user!, only: :new
+  before_action :authenticate_user!, only: :new
   skip_before_action :verify_atlassian_jwt!, only: :new
 
   def new
-    # move authenticate_user! to a before_action when we remove the jira_connect_proxy_create_branch feature flag
-    authenticate_user! if Feature.enabled?(:jira_connect_proxy_create_branch, current_user)
-
     @new_branch_data = new_branch_data
   end
 
   # If the GitLab for Jira Cloud app was installed from the Jira marketplace and points to a self-managed instance,
   # we route the user to the self-managed instance, otherwise we redirect to :new
   def route
-    if Feature.enabled?(:jira_connect_proxy_create_branch, current_user) && current_jira_installation.proxy?
+    if current_jira_installation.proxy?
       redirect_to "#{current_jira_installation.create_branch_url}?#{request.query_string}"
 
       return

config/feature_flags/gitlab_com_derisk/jira_connect_proxy_create_branch.yml

----
-name: jira_connect_proxy_create_branch
-feature_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/391432
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/149377
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/466462
-milestone: '17.2'
-group: group::import and integrate
-type: gitlab_com_derisk
-default_enabled: false

spec/controllers/jira_connect/branches_controller_spec.rb

@@ -89,17 +89,6 @@
           expect(response).to redirect_to("#{create_branch_url}?#{query_string}")
         end
       end
-
-      context 'when jira_connect_proxy_create_branch feature is disabled' do
-        before do
-          stub_feature_flags(jira_connect_proxy_create_branch: false)
-        end
-
-        it 'redirects to :new' do
-          get :route, params: params
-          expect(response).to redirect_to("#{new_jira_connect_branch_url}?#{query_string}")
-        end
-      end
     end
   end
 end