[Read Aloud] Wrap the Read Aloud font menu with cr-lazy-render.

Other menus to come.

This is to prevent menus from rendering unnecessarily, which can
contribute to latency.

Bug: 329676284
Change-Id: I6925fccaccc451ff27847b91a656f157ad1e9792
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5408062


Reviewed-by: Kristi Saney <kristislee@google.com>
Commit-Queue: Lauren Winston <lwinston@google.com>
Cr-Commit-Position: refs/heads/main@{#1280466}