Fluid inputs: FluidTextArea

[tay1orjones]

This issue is for providing the experimental fluid input variant, TextArea. This will span both design and development to lay the groundwork for additional fluid input components to be added to the system, #5416.

Checklist

• Fluid inputs: Text area docs carbon-website#3122
  • Add to fluid-input branch (do not merge)
  • Update "style" and "usage" tabs of component page to include Fluid variant
• Fluid inputs: Provide design tooling updates for TextInput
  • [Figma] Add "Fluid-input: TextArea" carbon-design-kit#564 (priority)
  • Sketch (backlogged)
• Fluid inputs: Add FluidTextArea experimental implementation #12020

Spec

Sketch file | Figma file