[Read aloud] Fix toggle race conditions and force install on toggle.

There were two bugs causing incorrect behavior- 1) the checked property
wasn't updating when enabledLangaugesInPrefs changed, and 2) the force
install was only happening when we previously had an install error
cached, which isn't the case upon first instantiation of read aloud.

Bug: 343990367
Change-Id: I60380c285029be8a87c119bfc7fed6a7f7420cc5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5614834


Reviewed-by: Lauren Winston <lwinston@google.com>
Commit-Queue: Eitan Goldberger <eitang@google.com>
Cr-Commit-Position: refs/heads/main@{#1312943}