Merge branch 'yorick/lb-safe-request-store' into 'master'

Use SafeRequestStore in the DB LB

See merge request gitlab-org/gitlab!70003

lib/gitlab/database/load_balancing/load_balancer.rb

@@ -245,7 +245,7 @@ module Gitlab
         end
 
         def request_cache
-          base = RequestStore[:gitlab_load_balancer] ||= {}
+          base = SafeRequestStore[:gitlab_load_balancer] ||= {}
           base[self] ||= {}
         end
       end