Clean up some types specified in dh.types.ts

- Will also have a follow up ticket to use the automatically generated types

Author: mofojed

packages/jsapi-types/src/dh.types.ts

@@ -336,6 +336,12 @@ export interface Figure extends Evented {
   close(): void;
 }
 
+export type WidgetExportedObject = {
+  type: string;
+  fetch: () => Promise<unknown>;
+  close: () => void;
+};
+
 export interface Widget {
   readonly EVENT_MESSAGE: string;
 
@@ -344,7 +350,10 @@ export interface Widget {
     listener: (event: unknown) => void
   ) => () => void;
   getDataAsBase64(): string;
+  getDataAsString(): string;
+  getDataAsU8(): Uint8Array;
   sendMessage: (message: string, references?: never[]) => void;
+  exportedObjects: WidgetExportedObject[];
 }
 
 export interface FigureDataUpdatedEvent {