Generate apex_available from c2a instead of a patch am: fd4214399a am: 8ef9e0875e am: a12ae846d2

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/protobuf/+/1689915

Change-Id: I398b241d29875de9749a5202aea91776bad7562b