[OpenAI] Prepare release script & publish samples (#29137)

### Packages impacted by this PR
@azure/openai

### Issues associated with this PR


### Describe the problem that is addressed by this PR
Run prepare release script and publish samples

sdk/openai/openai/CHANGELOG.md

@@ -1,6 +1,6 @@
 # Release History
 
-## 1.0.0-beta.12 (Unreleased)
+## 1.0.0-beta.12 (2024-04-01)
 
 ### Features Added
 
@@ -33,8 +33,6 @@ Changes to "bring your own data" features:
 
 - Fix a bug where `ChatCompletionsFunctionToolCall` did not expose the `index` property for the streaming mode.
 
-### Other Changes
-
 ## 1.0.0-beta.11 (2024-01-25)
 
 ### Bugs Fixed

sdk/openai/openai/samples/v1-beta/javascript/bringYourOwnData.js

@@ -45,10 +45,13 @@ async function main() {
     azureExtensionOptions: {
       extensions: [
         {
-          type: "AzureCognitiveSearch",
+          type: "azure_search",
           endpoint: azureSearchEndpoint,
-          key: azureSearchAdminKey,
           indexName: azureSearchIndexName,
+          authentication: {
+            type: "api_key",
+            key: azureSearchAdminKey,
+          },
         },
       ],
     },

sdk/openai/openai/samples/v1-beta/typescript/src/bringYourOwnData.ts

@@ -46,10 +46,13 @@ export async function main() {
     azureExtensionOptions: {
       extensions: [
         {
-          type: "AzureCognitiveSearch",
+          type: "azure_search",
           endpoint: azureSearchEndpoint,
-          key: azureSearchAdminKey,
           indexName: azureSearchIndexName,
+          authentication: {
+            type: "api_key",
+            key: azureSearchAdminKey,
+          },
         },
       ],
     },

sdk/openai/openai/src/rest/openAIClient.ts

@@ -20,7 +20,7 @@ export default function createClient(
 ): OpenAIContext {
   const baseUrl = options.baseUrl ?? `${endpoint}/openai`;
   options.apiVersion = options.apiVersion ?? "2024-03-01-preview";
-  const userAgentInfo = `azsdk-js-openai-rest/1.0.0-beta.11`;
+  const userAgentInfo = `azsdk-js-openai-rest/1.0.0-beta.12`;
   const userAgentPrefix =
     options.userAgentOptions && options.userAgentOptions.userAgentPrefix
       ? `${options.userAgentOptions.userAgentPrefix} ${userAgentInfo}`