test fix

Author: Guiners

genai/output-folder/generate_content_streaming_image_0.png

@@ -28,7 +28,7 @@ describe('imggen-mmflash-with-txt', async () => {
     this.timeout(180000);
     this.retries(5);
     await delay(this.test);
-    const generatedFileNames = await sample.generateContent(
+    const generatedFileNames = await sample.generateImage(
       projectId,
       location
     );