[Telemetry] Update popular 25 extensions list

Like it says on the tin.

TBR=tonyg@chromium.org

Review URL: https://codereview.chromium.org/122133002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242710 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242710