Remove all androidx source in dackka; migrate to verifyPrebuilts

We can do this now that we have KMP support. Compose is not KMP, but works without it.

Fixes: 229661142, 189228842
Test: adjusts several tests; coverage only increases
Change-Id: I15cfc777ddde6929b2e4b9286457229410c8b343
3224 files changed