[Telemetry SWX] Add Mahmoud and Roland to OWNERS

Add Mahmoud and Roland to Telemetry SWX OWNERS.

Change-Id: I538797ecc1dcc75d89e2be93c951c7959a5ae3e4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2275439Reviewed-by: Roland Bock <rbock@google.com>
Reviewed-by: Mahmoud Gawad <mgawad@google.com>
Reviewed-by: Giovanni Ortuño Urquidi <ortuno@chromium.org>
Commit-Queue: Oleh Lamzin <lamzin@google.com>
Cr-Commit-Position: refs/heads/master@{#784376}

chromeos/components/telemetry_extension_ui/OWNERS

 lamzin@google.com
+mgawad@google.com
 ortuno@chromium.org
+rbock@google.com
 
 # COMPONENT: Platform>Apps>SystemWebApps