WIP: POC fix for dev/core#5571.

[twomice]

Reference issue: https://lab.civicrm.org/dev/core/-/issues/5571

• This solves the stated problem (upon validation of required checkbox/radio fields), and my own initial, manual, testing shows it doesn't break validation of required fields of other types.

Other thoughts:

• I'm unfamiliar with the packages/ repo. Is a PR here even a reasonable thing to do?
• Adding params to a method doesn't "feel great", but this is just a POC.
• I'm unsure whether an equivalent fix would be relevant for similar method in these places:
  • packages/_ORIGINAL_/HTML/QuickForm/Renderer/ITStatic.php
  • packages/_ORIGINAL_/HTML/QuickForm/Renderer/ArraySmarty.php
  • packages/HTML/QuickForm/Renderer/ITStatic.php

[civibot]

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