[BUGFIX] Respect icon size defined by tree

The SVG Tree now builds a SVG-in-SVG element around all
icons (icon + overlay) to ensure the sizes are consistent
and can be positioned properly.

This fixes the issue that possible custom icons have
a different size.

Resolves: #86280
Releases: master
Change-Id: Icf39e74c398d149a9216a64551bdeb250ed2bf00
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/69147


Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>