slots_mapped_in_domain not using name of form

[ArjaanBuijk]

Rasa version: current master branch
Rasa SDK version: current master branch
Python version: 3.7
Operating system (windows, osx, ...): LInux

Issue:
I think that this line is not correct.

The value of self.name() returns the name of a FormValidation action, not the name of a form, so the outcome of this is always empty:

return list(domain.get("forms", {}).get(self.name(), {}).keys())

Error (including full traceback):
The form gets canceled.

Command or request that led to error:
See slack thread about financial-demo.