Fix to "Removing AudioMixerStatusReceiver and ParticipantStatistics"

In https://codereview.webrtc.org/1216133004/
level_indicator.h/cc should be removed from GN as well, which was forgotten.

BUG=webrtc:497
TBR=andrew@webrtc.org

Review URL: https://codereview.webrtc.org/1252993003 .

Cr-Commit-Position: refs/heads/master@{#9648}
1 file changed