react-native-firebase

fix(admob,android): null check activity in consent form (#2985)

* Added missing null checks for getCurrentActivity()

* Added null check in Consent module form.
Wrapped consentForm.show() with try-catch.

Co-authored-by: Mike Hardy <github@mikehardy.net>
Co-authored-by: Mike Diarmid <mike.diarmid@gmail.com>