[Autofill Assistant] Add new team members to OWNERS

Bug: NONE
Change-Id: I64d6dd4d6f66a6248ac55bd0d8de058d4cf63a7e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1971914Reviewed-by: Mathias Carlen <mcarlen@chromium.org>
Commit-Queue: Sandro Maggi <sandromaggi@google.com>
Cr-Commit-Position: refs/heads/master@{#725553}

components/autofill_assistant/OWNERS

 # Please keep these in alphabetical order
 arbesser@google.com
 gogerald@chromium.org
+hluca@google.com
 jdemeulenaere@chromium.org
 marianfe@google.com
 mcarlen@chromium.org
 rouslan@chromium.org
+sandromaggi@google.com
 szermatt@chromium.org
 
 # COMPONENT: UI>Browser>Autofill