Fix shell command bugs for supporting CTS test. Add service unit test. Fix javadoc. Test: unit test and cts test Ignore-AOSP-First: confidential feature BUG: 242480433 Change-Id: I0fd2950eea267d56fbd8e89ecc52fdd590992e75 Merged-In: I0fd2950eea267d56fbd8e89ecc52fdd590992e75 (cherry picked from commit 44eafb8f58e3ca6015594b4067520cc18e9ed3c3)