Replace api_files prop to api_contributions

As a process to enforce all api files in java_api_library to be passed
via java_api_contributions, this change removes the remaining usages of
api_files property in java_api_library and replace them with
java_api_contributions

Test: m --build-from-text-stub
Bug: 300964421
Change-Id: Iabeebef2cd0ab7c49d60c7e79d484df3237fced4