[TASK] Make an `NoopEventDispatcher` available to extensions

With the class in the general `EventDispatcher` namespace,
extensions can now use this class for their tests.

Also add unit tests for the moved class.

Resolves: #99070
Releases: main, 11.5
Change-Id: I69b94f50f68dcacfe036e8eb489ba6b82fbb585a
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/76570


Tested-by: core-ci <typo3@b13.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>