[BUGFIX] Prevent undefined array key in TypolinkSoftReferenceParser

Due to an invalid page link, e.g. "t3://page?type=123",
the "pageuid" key might not be set by PageLinkHandler.

This is now properly handled in the parser.

Resolves: #100510
Releases: main, 11.5
Change-Id: I0bc35cc1e3c0f5128ea52e3645faeaa5c600faaf
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78530


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>