Ability to provide custom onCloseFeedback function

[MariosKoni]

Is your feature request related to a problem? Please describe.
I need to provide feedback with my own close function. Apart from feedback closing the keyboard and the sheet, I need to be able to do other stuff.

Describe the solution you'd like
I would like to be able to pass a VoidCallback attribute to BetterFeedback constructor and this to override or run with the other commands in onCloseFeedback.