[TASK] Move pid resolving of AddRecord fieldControl into own method

The pid resolving in the `AddRecord` fieldControl is not sufficient in
all cases. To allow easier extension of the pid resolving without the
need to override the whole `render` method, the resolving is extracted
into an own method that can be extended in custom implementations.

Resolves: #95001
Releases: master
Change-Id: Ie71943aa6275e9d5e7a7e3295d968198f665d5ba
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/70767


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