Context

While finishing the React TextArea PR, we audited React Native TextArea and mobile onboarding usage.

Findings:

• @metamask/design-system-react-native TextArea still supports inputElement and textVariant.
• No production mobile caller was found passing inputElement to TextArea.
• The mobile onboarding SRP textarea flow uses SrpInput / SrpInputGrid with normal TextInput props such as multiline, style, inputStyle, and textAlignVertical; it does not require TextArea inputElement.
• The app-level inputElement usages found in mobile are TextField date-picker touch target cases, not TextArea.

Scope

• Remove inputElement support from React Native TextArea.
• Remove textVariant support from React Native TextArea so it keeps fixed TextArea typography.
• Move the shared TextArea type cleanup into this work if needed.
• Update React Native TextArea docs, stories, and tests.

Non-goals

• Do not remove inputElement from React Native TextField; mobile has known TextField use cases for custom date-picker inputs.