[BUGFIX] Supply origin to URL if domain is missing

The AJAX API fails to send a request if the API receives a non-absolute
URL like /typo3/index.php?foo=bar, since the domain is missing. To fix
this issue, the origin of the triggering request is added as well as
`base` argument of URL().

Resolves: #89893
Releases: master
Change-Id: Ice61a71fc8d4627e6d0b3b9d0f5ab524000361ab
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/62576


Tested-by: Susanne Moog <look@susi.dev>
Tested-by: Frank Nägler <frank.naegler@typo3.org>
Tested-by: TYPO3com <noreply@typo3.com>
Reviewed-by: Susanne Moog <look@susi.dev>
Reviewed-by: Frank Nägler <frank.naegler@typo3.org>