Remove unused title parameter.

It is always overridden by to humanized source branch name by
MergeRequests::BuilService, which is used by new_project_merge_request_path.

app/helpers/merge_requests_helper.rb

@@ -19,8 +19,7 @@ module MergeRequestsHelper
       source_project_id: event.project.id,
       target_project_id: target_project.id,
       source_branch: event.branch_name,
-      target_branch: target_project.repository.root_ref,
-      title: event.branch_name.titleize.humanize
+      target_branch: target_project.repository.root_ref
     }
   end