Form submit refactors for Site Warning & Share notebooks

[manfromjupyter]

Separating this to keep the PR small. Aims to work closer towards closing #639 and #848

DONE

1. Made site warning type/level buttons into an actual radio button instead of buttons people forget to click
2. Added support to clear of the field and for the submit button to be disabled when clearing data.
3. Got disable submit form working for Site Warnings, Share Notebook with users, and ....

Status since #848

Form	Summary	Disable/Enable support status
Admin - Site Warning#Create	Good (now)	Design only (but now disabled by default with this PR)
Admin - Site Warning#Edit	Good (now)	N/A - will be all filled out already by default, just is disabled upon removing fields by Design only.
Admin - Site Warning#Delete	Perfect (now)	DONE - always able to be clicked after site warning has been created. Hidden on new site warnings (now)
Admin - Site Warning#Clear (NEW)	Perfect (new)	DONE - always able to be clicked on new site warning.
Share Notebook with Users	Perfect (now)	DONE (with this PR)

[mcrutch]

info/error radio buttons styles are broken

[manfromjupyter]

@mcrutch Dark theme issue has been fixed

[mcrutch]

Is it intended to look this much worse? (Not just Dark theme)

Main

enforce-form-requirements

[manfromjupyter]

@mcrutch I think this is ready now. Consistently formatted checkboxes and radio button fields in inlined forms and modal forms. Affects Propose Review, Feedback form, and Site Warning forms