Remove services.speech

services.speech-sources had no files in it,
so services.speech was just being built as
an empty jar file.

Bug: 210751803
Test: m services.speech && unzip out/target/product/generic_arm64/obj/JAVA_LIBRARIES/services.speech_intermediates/javalib.jar produces "zipfile is empty"
Change-Id: Id98db9ee98d71f639ef6104ad7fece92940944a9