fix: unsafe embed builder field normalization (#7418)

packages/builders/src/util/jsonEncodable.ts

@@ -0,0 +1,14 @@
+export interface JSONEncodable<T> {
+	/**
+	 * Transforms this object to its JSON format
+	 */
+	toJSON: () => T;
+}
+
+/**
+ * Indicates if an object is encodable or not.
+ * @param maybeEncodable The object to check against
+ */
+export function isJSONEncodable(maybeEncodable: unknown): maybeEncodable is JSONEncodable<unknown> {
+	return maybeEncodable !== null && typeof maybeEncodable === 'object' && 'toJSON' in maybeEncodable;
+}