audio policy: update permission check for REMOTE_SUBMIX audio source.

Do not request RECORD_AUDIO permission when capturing from audio source
REMOTE_SUBMIX as this is not capturing from an actual microphone but from
a redirection if the audio output instead.
Now enforce either MODIFY_AUDIO_ROUTING (aligned with dynamic audio
policy registration).

Also fix a similar issue with audio source ECHO_REFERENCE where RECORD_AUDIO
permission was requested in addition to CAPTURE_AUDIO_OUTPUT.

Bug: 186581697
Test: GTS AudioCaptureTest#testFixedVolumeRemoteSubmixSetup,
RemoteSubmixTest#testRecordFromRemoteSubmix, AudioPolicyTest
Test: CTS AudioRecordTest#testRestrictedAudioSourcePermissions,
NoCaptureAudioOutputPermissionTest#testCreateAudioRecord, AudioPlaybackCaptureTest

Change-Id: Icfaa60af99bb5813ec4572e092c94a94090b7d8d