[TASK] Avoid TypoScriptParser->getVal()

To further reduce usages of old TypoScriptParser,
the "resolve '=<' reference operator" logic in
ContentObjectRenderer is streamlined and avoids
using the TypoScriptParser->getVal() helper method.

Resolves: #99060
Related: #97816
Releases: main
Change-Id: Ibf131238b5350e77b7fac6f1006d8da54925213d
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/76552


Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>