PrebuildEtcModule no longer implements OutputFiles method

In the context of incremental soong, the output files
inter-module-communication will be through OutputFilesProvider.
The OutputFileProducer interface will be deprecated.

These module types are included in this change:
linker_config
llndk_libraries_txt
sanitizer_libraries_txt
java_sdk_library_xml
vndksp_libraries_txt
vndkcore_libraries_txt
vndkprivate_libraries_txt
vndkpublic_libraries_txt

Test: CI
Bug: 339477385
Change-Id: I35575bbad137df5ff8001db9a61ba5b3d13eaa6d