Update Contenet Capture API discription

There are missing API description at getServiceComponentName in
ContentCaptureManager. Some errors may occur and an exception may be
thrown. So update the javadoc to remind user to handle.

Fixes: 203368373
Test: make
Change-Id: I979c81c74cda4e50627dc0c83ae7c33b333b9255
1 file changed