Fix RequestProfiler::Middleware error when code is reloaded in development

Closes #20452

CHANGELOG

@@ -40,6 +40,7 @@ v 8.11.0 (unreleased)
   - Change requests_profiles resource constraint to catch virtually any file
   - Reduce number of queries made for merge_requests/:id/diffs
   - Sensible state specific default sort order for issues and merge requests !5453 (tomb0y)
+  - Fix RequestProfiler::Middleware error when code is reloaded in development
 
 v 8.10.3 (unreleased)
   - Fix hooks missing on imported GitLab projects

config/initializers/request_profiler.rb

+require 'gitlab/request_profiler/middleware'
+
 Rails.application.configure do |config|
   config.middleware.use(Gitlab::RequestProfiler::Middleware)
 end

lib/gitlab/request_profiler/middleware.rb

 require 'ruby-prof'
+require 'gitlab/request_profiler'
 
 module Gitlab
   module RequestProfiler