[TASK] Make honeypot field accessible

The honeypot field now passes the accessibility tests WCAG 2.0 (tested
with Google Lighthouse).

Instead of inserting a label tag or a title attribute - which would be
counterproductive by revealing the purpose of the honeypot - the patch
adds an aria-hidden attribute.

Resolves: #75591
Releases: master, 8.7
Change-Id: Ie4b0b7a245f5c0edf3e01ece60dcb638b2f9bdc1
Reviewed-on: https://review.typo3.org/56992


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Susanne Moog <susanne.moog@typo3.org>
Tested-by: Susanne Moog <susanne.moog@typo3.org>
Reviewed-by: Ralf Zimmermann <ralf.zimmermann@tritum.de>
Tested-by: Ralf Zimmermann <ralf.zimmermann@tritum.de>