[Android] Update OWNERS information (appmenu)

https://docs.google.com/document/d/1fmaUj2L_ZOjtwLRf6Bm7OBfUR2XSPb5-ICnxtpfsI70

Bug: 1112872
Change-Id: I85ef46f55bfac62b2c653d06eab4095fdd21a101
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2337265
Auto-Submit: Fred Mello <fredmello@chromium.org>
Reviewed-by: Theresa  <twellington@chromium.org>
Commit-Queue: Theresa  <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#794744}

chrome/android/javatests/src/org/chromium/chrome/browser/app/appmenu/OWNERS

-file://chrome/browser/ui/android/appmenu/OWNERS
+file://chrome/android/java/src/org/chromium/chrome/browser/app/appmenu/OWNERS

chrome/android/junit/src/org/chromium/chrome/browser/app/appmenu/OWNERS

+file://chrome/android/java/src/org/chromium/chrome/browser/app/appmenu/OWNERS

chrome/browser/ui/android/appmenu/OWNERS

 twellington@chromium.org
 
-# COMPONENT: UI>Browser>Mobile
+# COMPONENT: UI>Browser>Mobile>AppMenu
+# TEAM: chrome-android-app@chromium.org
+# OS: Android