Extends usage of Media.MicrophoneMuted UMA with one year.

We still look at this metric from time to time when debugging audio
issues in clients like Meet.

Bug: 1251230
Change-Id: I8a4aad80257ad77b6ceb3a89df4eec7549ee4e06
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3197686
Commit-Queue: Henrik Andreasson <[email protected]>
Reviewed-by: Caitlin Fischer <[email protected]>
Cr-Commit-Position: refs/heads/main@{#927558}

Author: henrikand

tools/metrics/histograms/metadata/media/histograms.xml

@@ -2891,12 +2891,12 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
 </histogram>
 
 <histogram name="Media.MicrophoneMuted" enum="MicrophoneMuteResult"
-    expires_after="2021-10-31">
+    expires_after="2022-10-31">
   <owner>[email protected]</owner>
   <owner>[email protected]</owner>
   <summary>
     Heuristically detects if the user has muted the microphone or not. Measured
-    approximately four times per minute.
+    approximately four times per minute while an audio input stream is active.
   </summary>
 </histogram>