[Figma] Add "Fluid inputs: TextInput"

[aagonzales]

Fluid inputs: Provide design tooling updates for TextInput to v11 Figma kit

• [x] Create a branch for all Fluid input work in each theme file (do not merge until all fluid inputs have been completed)
• [x] White theme
• [x] Gray 10 theme
• [x] Gray 90 theme
• [x] Gray 100 theme

Spec

Figma file | Sketch file

[thyhmdo]

Except for skeleton state, this is ready for review