Implemented API-review suggested changes on GradientDrawable

--Added @Px annotations to pixel related parameters in added APIs
--Added @FloatRange annotation to float based APIs
(thickness/inner)Ratio
--Added error checking to invalid ratio arguments to
set(Thickness/Inner)ratio

Bug: 126375868
Bug: 126701500
Test: Added CTS tests to verify parameter validation logic
Change-Id: I8ca70f38edd18f68c168d4d6e2c93bcb9b64c488