fixes#1464
The user preference changes were not broadcasting correctly in firefox
because it has a race condition wherein the broadcast message was being
received by a peer tab before the localStorage data was ready to be
consumed in that tab.
### Change Type
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- [x] `patch` — Bug Fix
- [ ] `minor` — New Feature
- [ ] `major` — Breaking Change
- [ ] `dependencies` — Dependency Update (publishes a `patch` release,
for devDependencies use `internal`)
- [ ] `documentation` — Changes to the documentation only (will not
publish a new version)
- [ ] `tests` — Changes to any testing-related code only (will not
publish a new version)
- [ ] `internal` — Any other changes that don't affect the published
package (will not publish a new version)
### Test Plan
1. in firefox, have two tabs open in the same user context.
2. toggle dark mode.
3. the change should propagate to the other tab
b742783577