Removing myself from content/browser/speech owners

Change-Id: I00bb410f08027040b1adc7a7d7f5ebe33314fe97
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2228536Reviewed-by: Tommi <tommi@chromium.org>
Commit-Queue: Tommi <tommi@chromium.org>
Commit-Queue: Olga Sharonova <olka@chromium.org>
Auto-Submit: Olga Sharonova <olka@chromium.org>
Cr-Commit-Position: refs/heads/master@{#800509}

content/browser/speech/OWNERS

 # Speech recognition
-olka@chromium.org
+file://third_party/blink/renderer/modules/speech/OWNERS
 
 # Text-to-speech
 per-file *tts_*=dmazzoni@chromium.org