`FilePart` interface not exported

[Saran33]

Description

The newly added FilePart interface is not exported as are the other content parts.

Code example

import type {
  CoreMessage,
  FilePart,
  ImagePart,
  TextPart,
  ToolCallPart,
  ToolResultPart,
} from 'ai';
// Module '"ai"' declares 'FilePart' locally, but it is not exported.ts(2459)

Additional context

No response