Customize height of button #484

Is your feature request related to a problem you're having? Please describe.
The buttonHeight property is inaccessible and would like the dimensions of the button exposed.

Describe the solution you'd like
Add properties to the model to allow for more visual control

Describe alternatives you've considered
none

Additional context
This facilitates making the Google Sign In button the same size as the Sign in with Apple buttons for a more consistent UI.