[Read Aloud] Add event listeners for line spacing and theme.

Bug: 1465029
Change-Id: I24a24b67f60d95973f1827db978d0df293294d83
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4786933


Reviewed-by: Kristi Saney <kristislee@google.com>
Commit-Queue: Lauren Winston <lwinston@google.com>
Cr-Commit-Position: refs/heads/main@{#1184843}