Update :release_search_filter to default to on

This commit enables the `release:` search filter by default.

app/controllers/projects/issues_controller.rb

@@ -44,7 +44,7 @@ class Projects::IssuesController < Projects::ApplicationController
 
   before_action do
     push_frontend_feature_flag(:vue_issuable_sidebar, project.group)
-    push_frontend_feature_flag(:release_search_filter, project)
+    push_frontend_feature_flag(:release_search_filter, project, default_enabled: true)
   end
 
   respond_to :html

app/controllers/projects/merge_requests_controller.rb

@@ -24,7 +24,7 @@ class Projects::MergeRequestsController < Projects::MergeRequests::ApplicationCo
 
   before_action do
     push_frontend_feature_flag(:vue_issuable_sidebar, @project.group)
-    push_frontend_feature_flag(:release_search_filter, @project)
+    push_frontend_feature_flag(:release_search_filter, @project, default_enabled: true)
   end
 
   around_action :allow_gitaly_ref_name_caching, only: [:index, :show, :discussions]