[BUGFIX] Re-add missing t3editor panel label

The t3editor panel label was removed by accident in
https://review.typo3.org/c/Packages/TYPO3.CMS/+/66225
because it was passed via the invalid textarea alt attribute.

Re-add this label via data-codemirror-config attribute.

Releases: master, 10.4
Resolves: #93115
Related: #92633
Change-Id: Ib743fa28a0249de142ac1d112865b1f2c7bdc216
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/67189


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>