Update contextmenu/OWNERS

Change-Id: I620dd3836672a91e681842407c426c3b817adcb6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2430303
Commit-Queue: Sinan Sahin <sinansahin@google.com>
Reviewed-by: Theresa  <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810389}

chrome/android/java/src/org/chromium/chrome/browser/contextmenu/OWNERS

 twellington@chromium.org
+sinansahin@google.com
 
 # COMPONENT: UI>Browser>Mobile>ContextMenu
 # TEAM: chrome-android-app@chromium.org

chrome/browser/contextmenu/OWNERS

 jinsukkim@chromium.org
-sinansahin@chromium.org
+sinansahin@google.com
 
 # TEAM: clank-modularization@chromium.org
-# COMPONENT: UI>Browser>Mobile
+# COMPONENT: UI>Browser>Mobile>ContextMenu
 # OS: Android