[BUGFIX] Consider empty or invalid password policy reference

In case `$GLOBALS['TYPO3_CONF_VARS']['BE']['passwordPolicy']`
is disabled or set to a preset that actually does not exist,
the backend editing view should not issue JavaScript errors
on the missing `#password-policy-info` element.

Resolves: #102668
Releases: main, 12.4
Change-Id: Iafb418254f73f379364b04c5d45d33111bef7d13
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/82123


Reviewed-by: Oliver Bartsch <bo@cedev.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Bartsch <bo@cedev.de>