Prefetch pathLastCommit GraphQL with StartupJS

Issue: https://gitlab.com/gitlab-org/gitlab/-/issues/293855

app/views/projects/show.html.haml

+- current_route_path = request.fullpath.match(/-\/tree\/[^\/]+\/(.+$)/).to_a[1]
+- add_page_startup_graphql_call('repository/path_last_commit', { projectPath: @project.full_path, ref: current_ref, path: current_route_path || "" })
 - @content_class = "limit-container-width" unless fluid_layout
 - @skip_current_level_breadcrumb = true