Fix SendApplicationAnswerMailHandler not supplying enough parameters

[BentiGorlich]

SendApplicationAnswerMailHandler was not supplying the kernel interface parameter to the base class, fix that

[BentiGorlich]

I looked through all the message handlers and could not find another one missing the second parameter

[melroy89]

I think this was not the first similar error we discovered. So I'm saying this is the second time we found this bug exact bug.

Q: Is it possible to find any remaining issues in the code base? Maybe some intelligent PHP analyzer tool or something? Since we also have no way of knowing when this could happen again, all the tests are passing as well. Including Psalm before the issue is fixed in this PR I mean.

[BentiGorlich]

I searched for it with a reference search in PHPStorm, I don't think that we can search more in depth than that. I think we had this problem before, but with a different message handler. I think the problem was that the message handler adaption was being done at the same time as this handler was introduced and then it was just forgotten...