disable kotlin java_imports for mixed builds

These Kotlin JARs contain class files under the META-INF directory that
are incorrectly parsed in gen_jarjar.py causing the Jarjar tool to error.

Bug: 243098369
Bug: 217750501
Test: build/bazel/ci/mixed_droid.sh
Change-Id: I62aaf086dc91d868a8d653f7fdb2c111bdc96097