[BUGFIX] Ignore csp.yaml file when saving site configuration

The csp.yaml shouldn't be taken into account when merging current and
new site configuration via the GUI.

Resolves: #101626
Releases: main, 12.4
Change-Id: Ib08b7707cfb43733985b0c7aa5bf12bcc5fa603c
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/80480


Tested-by: Nikita Hovratov <nikita.h@live.de>
Reviewed-by: Nikita Hovratov <nikita.h@live.de>
Tested-by: core-ci <typo3@b13.com>