[MM-61514] Fix errcheck issues in server/channels/app/web_broadcast_hooks_test.go (#29213)

Co-authored-by: Ben Schumacher <ben.schumacher@mattermost.com>
Co-authored-by: Caleb Roseland <caleb@calebroseland.com>

server/.golangci.yml

@@ -111,7 +111,6 @@ issues:
         channels/app/team.go|\
         channels/app/team_test.go|\
         channels/app/upload.go|\
-        channels/app/web_broadcast_hooks_test.go|\
         channels/app/webhook_test.go|\
         channels/jobs/batch_worker_test.go|\
         channels/jobs/helper_test.go|\