Fix responsiveness of the RuleLabel buttons

[solkaz]

Description

Refactors the RuleLabel buttons to use flex-box properties, making them more responsive Also removes the padding from the Filter and Annotation titles, so there's more room for the content in their respective sections

Motivation and Context

Fixes #517

Checklist:

• [x] My code follows the code style of this project.
• [x] I have added tests to cover my changes.
• [x] All new and existing tests passed.

Browsers

• [x] Chrome
• [x] Firefox
• [x] Safari
• [ ] Mobile:
• [ ] Other:

Screenshots (if appropriate):

[Hopding]

This is definitely a nice improvement. However you removed the padding between the filters. Was that intentional? I'd prefer to keep it.

[thebho]

It was a compromise to use dynamic sizing

[Hopding]

Why is padding incompatible with resizing?

[solkaz]

*Margin, not padding. For some reason, adding margins breaks flexbox properties.

[thebho]

Yeah, this was the best of the options i saw. There is a slack history from yesterday if you are interested