[TASK] Adapt slot signature for CMS 7

There is a change in the signature of the dispatched Signal 'afterExtensionConfigurationWrite' in CMS 7. An additional parameter $extensionKey comes in as first one.

see: https://git.typo3.org/Packages/TYPO3.CMS.git/commit/2fc3ec6b9c8550dc9cb606a74dcf52d8ae22b3d7