CarrierDefaultApp remove debuggable=true

This was added in ag/20462243 for unit tests to pass, but we need to
investigate a new way to use mockito inline without making the entire
app debuggable. Note that after this change CarrierDefaultApp tests will
fail.

Test: build
Bug: 264426585
Bug: 259503002
Change-Id: Ia1b41d59e7cbec55c25966ec1e3d4a9b51c4cadd