Refactored FAB settings page

[hjiangsu]

Pull Request Description

Review with whitespace off

This PR refactors the FAB settings page to follow similar conventions of the other recently refactored setting pages. Main changes include:

• Changed to using slivers instead of previous SingleChildScrollView
• Updated all text to use localized text when available. Almost all the text should already have localized versions (except a few labels, and the information section)
• Refactored the information section to use markdown instead of multiple text widgets
• Added expand/collapse icon to information page

Issue Being Fixed

Issue Number: N/A

Screenshots / Recordings

original	refactored

When switching to a different language with the refactor:

spanish	norwegian

Checklist

• Did you update CHANGELOG.md?
• Did you use localized strings where applicable?
• Did you add semanticLabels where applicable for accessibility?

[micahmo]

Looks good to me! Nice housekeeping stuff. And good idea to use markdown for the body of text.