Tweak vertical alignment of tab badges

[matthew-white]

This PR makes small adjustments to the vertical alignment of tab badges. It attempts to address getodk/central#671 (comment).

What has been done to verify that this works as intended?

Trying it out locally.

Before submitting this PR, please make sure you have:

• run npm run test and npm run lint and confirmed all checks still pass OR confirm CircleCI build passes
• verified that any code or assets from external sources are properly credited in comments or that everything is internally sourced

[lognaturel]

@matthew-white will put this on the QA server so Szymon can verify it because he's the only one who can reproduce currently.