feat(generative-ai): Add basic samples for Gemini / VertexAI inference (#3670)

* feat(generative-ai): Add sample for basic text generation.

* chore: fix lint issues

* feat: Add basic multimodal example

* chore: add header

* feat: Add streaming inference example

* feat: Add example for multimodal streaming response

* fix: Fix some tests that were not running correctly

* chore: Clarify test names

* fix: Adjust cloud storage bucket and argurment order for consistency

* chore: fix lint errors

* chore: Update some tests and prompt text to be clearer

* Update model to the correct multimodal model
* Clarify multimodal prompt based on order

* chore: Update function calling stream model to address flaky test.

Author: arbrown

generative-ai/snippets/inference/nonStreamMultiModalityBasic.js

@@ -45,7 +45,7 @@ async function generateContent(
               mime_type: 'image/jpeg',
             },
           },
-          {text: 'Are following video and image correlated?'},
+          {text: 'Are this video and image correlated?'},
         ],
       },
     ],

generative-ai/snippets/inference/streamMultiModalityBasic.js

@@ -45,7 +45,7 @@ async function generateContent(
               mime_type: 'image/jpeg',
             },
           },
-          {text: 'Are following video and image correlated?'},
+          {text: 'Are this video and image correlated?'},
         ],
       },
     ],

generative-ai/snippets/test/function-calling/functionCallingStreamChat.test.js

@@ -30,7 +30,7 @@ describe('Generative AI Function Calling Stream Chat', () => {
    */
   // const projectId = 'YOUR_PROJECT_ID';
   // const location = 'YOUR_LOCATION';
-  // const model = 'gemini-1.0-pro';
+  // const model = 'gemini-1.5-pro-preview-0409';
 
   it('should create stream chat and begin the conversation the same in each instance', async () => {
     const output = execSync(

generative-ai/snippets/test/inference/nonStreamMultiModalityBasic.test.js

@@ -30,7 +30,7 @@ describe('Generative AI Multimodal Text Inference', () => {
    */
   // const projectId = 'YOUR_PROJECT_ID';
   // const location = 'YOUR_LOCATION';
-  // const model = 'gemini-1.0-pro';
+  // const model = 'gemini-1.5-pro-preview-0409';
 
   it('should generate text based on a prompt containing text, a video, and an image', async () => {
     const output = execSync(