[TASK] Use correct method visibility in Lit elements

The methods `createRenderRoot()` and `render()` are considered being
protected, but were public in some cases my mistake. This doesn't have
any functional impact, but is now fixed nonetheless.

Resolves: #101689
Releases: main, 12.4
Change-Id: I6bb88f90a8a44e0118dd8203433a54517b5dfa2f
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/80561


Tested-by: Benjamin Franzke <ben@bnf.dev>
Reviewed-by: Benjamin Franzke <ben@bnf.dev>
Tested-by: core-ci <typo3@b13.com>