[TASK] DatabaseRecordList: Drop property `HTMLcode`

The property `HTMLcode` was only used to collect the output for the
tables in `generateList()`. Therefore, `generateList()` returns the
collected output and the property `HTMLcode` has been removed.

Releases: master
Resolves: #92130
Change-Id: I938174a4f25b08281b54883c7f0f3cf62c70c9f8
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/65504


Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>