style: Feedback component style refinement

[ianjon3s]

What does this PR do?

Small styling refinements to @jamdelion's work on the feedback component:

• Updates feedback text input to be textarea rather than rich text (editor) input
• Updates rating buttons to be responsive to width
• Updates selected rating button to be consistent with styling of selected radio grid (blue border)
• Increases disclaimer text size to our minimum (16px) type size
• Small spacing refinements

Preview:
(feature flag required: window.featureFlags.toggle("FEEDBACK_COMPONENT"))

Before:

After:

[github-actions]

Pizza

Deployed 2006976 to https://3924.planx.pizza.

Useful links:

• Editor
• Storybook
• Hasura
• API
• ShareDB