[TASK] Add unit test for colorpicker TCA migration

Also fixes the case when wizards array becomes empty.
We can than safely unset the complete wizards key.

Resolves: #75716
Releases: master
Change-Id: I8b0cc65823b2ec6bf8598b21be2dae3bb174e58b
Reviewed-on: https://review.typo3.org/47731


Reviewed-by: Susanne Moog <typo3@susannemoog.de>
Tested-by: Susanne Moog <typo3@susannemoog.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>