Bubble API: add support for URI based icons

I would ultimately like to restrict icons to be TYPE_URI_ADAPTIVE_BITMAP,
however, that would break existing app behaviour. Let's log a warning
and hope that we can change it to be one of the URI based icons in the
future.

Test: atest NotificationManagerTest
Bug: 138943209
Bug: 144352570
Change-Id: I044f035571fcaa817b19d8ff330fb22b4addf970