[BUGFIX] Properly handle diff while updating meta data

The existing solution using `array_diff` did not work, as it only
respects values, not a combination with keys.

Given an existing record with some empty values would prevent unsetting
another value with an empty. The same would apply for setting another
value to an existing value.

That's why we change to `array_diff_assoc`, which handles proper diff of
value in combination with key.

Resolves: #103708
Releases: main, 12.4
Change-Id: I36adbc8279e5160c33e8feffcd8741c30c667adc
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/84000


Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>