[BUGFIX] Hide form validators label when no one is available

With the deprecation removal of regular expressions
based EXT:form validators in #101070, the set of available
validators for the form element type URL became empty.
(See EXT:form/Configuration/Yaml/FormElements/Url.yaml)

Instead of only removing the select element from the DOM,
the entire form-group is now removed, in order to also hide
the corresponding <label> tag, as such a stray label tag
isn't helpful for an enduser and is therefore actually even
invalid HTML (as the reference to an input element is missing).

Resolves: #101749
Related: #101070
Releases: main, 12.4, 11.5
Change-Id: Ib0d34e94e2c3ba109133dac64374f04f7c91329b
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/80730


Tested-by: core-ci <typo3@b13.com>
Tested-by: Benjamin Franzke <ben@bnf.dev>
Reviewed-by: Benjamin Franzke <ben@bnf.dev>