fix(plugin-form-builder): export radio field type (#11908)

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### What?

### Why?

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Fixes #

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### What?
[#11716](#11716) introduced
the `RadioField` component. This PR exports the type for use by
end-users.

### Why?
To allow end-users to utilize the type as expected with
`plugin-form-builder`.

### How?
Adds the `RadioField` interface to the list of exported plugin types.

Fixes #11806

Author: akhrarovsaid

packages/plugin-form-builder/src/exports/types.ts

@@ -20,6 +20,7 @@ export type {
   PaymentField,
   PaymentFieldConfig,
   PriceCondition,
+  RadioField,
   Redirect,
   SelectField,
   SelectFieldOption,