Support downscaling of Drawable icons in LocalImageResolver

LocalImageResolver only enforced downscaling for Uri-based Icons at this point. This still allowed app developers to provide large bitmaps as a resource or as a bitmap payload itself. This change also verifies these new types of bitmaps.
Also adds an external size parameter to image resolver so different widgets can use it - right now the upper limit was hardcoded in pixels.

Bug:218845090
Bug:210690571

Test: Manually on device - tested on Raven and new Pixel with multiple
                       notification sizes via notification test apk.
      Unit tests
Change-Id: I504694cb27953bc7950669b1b48f90d2e9c6a68d