Fixed Joomla menu z-index regression

[vingle]

Overview

Fixes z-index ordering originally described https://civicrm.stackexchange.com/questions/26858/anyone-else-seeing-an-overlapping-admin-civi-menu-bug-with-joomla-3-8-13-and-civ

Before

Technical Details

Works with and without Shoreditch

Comments

For more details see #12947

[civicrm-builder]

Can one of the admins verify this patch?

[civibot]

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[pradpnayak]

This is good to merge!

Thanks @vingle for the PR :)

[vingle]

Thanks @pradpnayak

[eileenmcnaughton]

phew!