[BUGFIX] Populate href lang URI only if the link is available

If there are e.g., records that have no translation, the
HrefLangGenerator outputs the site-base URL. Expected is that the entry
for this page is suppressed.

Change-Id: I6fbd4dd00955906dff13c0e5aceea6804c52dd1b
Resolves: #88032
Releases: master, 9.5
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/60350


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Jörg Bösche <typo3@joergboesche.de>
Tested-by: Richard Haeser <richard@maxserv.com>
Reviewed-by: Jörg Bösche <typo3@joergboesche.de>
Reviewed-by: Richard Haeser <richard@maxserv.com>