chore: move image part before text part in vertex requests (#3595)

Author: LukeSchlangen

generative-ai/snippets/nonStreamingMultipartContent.js

@@ -52,7 +52,7 @@ async function createNonStreamingMultipartContent(
   };
 
   const request = {
-    contents: [{role: 'user', parts: [textPart, filePart]}],
+    contents: [{role: 'user', parts: [filePart, textPart]}],
   };
 
   console.log('Prompt Text:');

generative-ai/snippets/sendMultiModalPromptWithVideo.js

@@ -40,15 +40,15 @@ async function sendMultiModalPromptWithVideo(
       {
         role: 'user',
         parts: [
-          {
-            text: 'What is in the video?',
-          },
           {
             fileData: {
               fileUri: 'gs://cloud-samples-data/video/animals.mp4',
               mimeType: 'video/mp4',
             },
           },
+          {
+            text: 'What is in the video?',
+          },
         ],
       },
     ],

generative-ai/snippets/streamMultipartContent.js

@@ -53,7 +53,7 @@ async function createStreamMultipartContent(
   };
 
   const request = {
-    contents: [{role: 'user', parts: [textPart, filePart]}],
+    contents: [{role: 'user', parts: [filePart, textPart]}],
   };
 
   console.log('Prompt Text:');