[TASK] Drop dev dependency phpspec/prophecy

The mocking framework prophecy is considered dead and is already dropped
in phpunit. All occurrences in the codebase have been replaced with
corresponding phpunit mocks or have been converted to functional tests.

This patch removes the composer dependency and allows to remove the
workarounds for ignoring the php platform checks in the test setup.

Run command:
> composer remove --dev \
phpspec/prophecy \
phpspec/prophecy-phpunit \
jangregor/phpstan-prophecy

Resolves: #99431
Releases: main
Change-Id: I3520a209f32592362e75cdd810f1db2b9e69d149
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/77234


Reviewed-by: Torben Hansen <derhansen@gmail.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Georg Ringer <georg.ringer...