Make checkboxes dark in dark theme

[rakleed]

First time contributor checklist:

• I have read the README and Contributor Guidelines
• I have signed the Contributor Licence Agreement

Contributor checklist:

• My contribution is not related to translations.
• My commits are in nice logical chunks with good commit messages
• My changes are rebased on the latest main branch
• A yarn ready run passes successfully (more about tests here)
• My changes are ready to be shipped to users

Description

Make checkboxes dark in a dark theme. I tested it with Signal Desktop for macOS.

Before:

After:

[josh-signal]

@rakleed can you run prettier on the files?

[rakleed]

If I format a file locally using the Prettier plugin in WebStorm, then it does not change in any way. And when I run yarn test I get the same error as in GitHub Actions.

[josh-signal]

run yarn format

[rakleed]

Done.

[josh-signal]

Thanks! It'll be on the next release.