Let widget driver send error details (#28357)

* Let widget driver send error details

* Match new widget API types

* Don't @link across packages

in case web documentation generation disallows it.

* Update matrix-widget-api

* Update matrix-js-sdk

Include matrix-org/matrix-js-sdk#4507 to fix playwright CI

src/stores/widgets/StopGapWidgetDriver.ts

@@ -24,6 +24,7 @@ import {
     WidgetDriver,
     WidgetEventCapability,
     WidgetKind,
+    IWidgetApiErrorResponseDataDetails,
     ISearchUserDirectoryResult,
     IGetMediaConfigResult,
     UpdateDelayedEventAction,
@@ -33,6 +34,7 @@ import {
     ITurnServer as IClientTurnServer,
     EventType,
     IContent,
+    MatrixError,
     MatrixEvent,
     Room,
     Direction,
@@ -689,4 +691,15 @@ export class StopGapWidgetDriver extends WidgetDriver {
         const blob = await response.blob();
         return { file: blob };
     }
+
+    /**
+     * Expresses a {@link MatrixError} as a JSON payload
+     * for use by Widget API error responses.
+     * @param error The error to handle.
+     * @returns The error expressed as a JSON payload,
+     * or undefined if it is not a {@link MatrixError}.
+     */
+    public processError(error: unknown): IWidgetApiErrorResponseDataDetails | undefined {
+        return error instanceof MatrixError ? { matrix_api_error: error.asWidgetApiErrorData() } : undefined;
+    }
 }