fix(qm-object-cache): fix closing markup for tabs nesting

[mae829]

Description

Fix for one of the Query Monitor plugins calling the closing markup at the end of tabs.
The existing code will not call the closing markup if there's no group_stats for object cache causing some of the QM content to not display.

Before and after:

Changelog Description

Fix broken markup call in Query Monitor plugin for object cache.

Fix broken markup call in Query Monitor plugin for object cache when there is no group stats.

Pre-review checklist

Please make sure the items below have been covered before requesting a review:

• This change works and has been tested locally (or has an appropriate fallback).
• This change works and has been tested on a Go sandbox.
• This change has relevant unit tests (if applicable).
• This change uses a rollout method to ease with deployment (if applicable - especially for large scale actions that require writes).
• This change has relevant documentation additions / updates (if applicable).
• I've created a changelog description that aligns with the provided examples.

Pre-deploy checklist

• VIP staff: Ensure any alerts added/updated conform to internal standards (see internal documentation).

Steps to Test