Turn on bp2build_deps by default

This prevents bp2buld conversion of modules which have transitive deps
that are not converted.

This does not change most allowlist semantics -- that change is still to
come. As a result, this effectively removes conversion of a few modules
which were previously converted under old semantics, however, these
modules are not currently used in any meaningful bazel builds, and will
be fixed at a later time.

Test: bp2build.sh
Test: m nothing
Test: manually spotchecked allowlisted modules in metrics to ensure the
diffs were minor
Test: manually verified bp2build performance regresses by about 0.4s

Change-Id: Id5c44fa5394917b28a3e707a81555b9e467d6621