Problem

• Add accesibility tests and finish Textarea's implementation subsection: Textarea Convergence  #21845
• Add Textarea to unstable components.
• Finish AvatarGroup's spec.
• Finish AvatarGroup's initial implementation: react-avatar: Adding initial implementation of AvatarGroup. #22736

NOTE: AvatarGroup's design spec is still WIP.

Appetite

2-3 weeks