Update @typespec/http-client-csharp to 1.0.0-alpha.20251020.2 (#769)

- Updated @typespec/http-client-csharp from 1.0.0-alpha.20251009.7 to 1.0.0-alpha.20251020.2
- Updated Microsoft.TypeSpec.Generator.ClientModel from 1.0.0-alpha.20251009.7 to 1.0.0-alpha.20251020.2
- Regenerated OpenAI SDK code with new generator version
- Updated centrally managed package-lock.json file with new dependency versions

Co-authored-by: GitHub Action <[email protected]>

Author: github-actions[bot]

codegen/generator/src/OpenAI.Library.Plugin.csproj

@@ -8,7 +8,7 @@
     </PropertyGroup>
 
     <ItemGroup>
-      <PackageReference Include="Microsoft.TypeSpec.Generator.ClientModel" Version="1.0.0-alpha.20251009.7" />
+      <PackageReference Include="Microsoft.TypeSpec.Generator.ClientModel" Version="1.0.0-alpha.20251020.2" />
     </ItemGroup>
 
   <!-- Copy output to package dist path for local execution and  -->

codegen/package.json

@@ -29,10 +29,10 @@
   ],
   "dependencies": {
     "@open-ai/plugin": "file:",
-    "@azure-tools/typespec-client-generator-core": "0.60.0",
-    "@typespec/http-client-csharp": "1.0.0-alpha.20251009.7",
-    "@typespec/http": "1.4.0",
-    "@typespec/openapi": "1.4.0"
+    "@azure-tools/typespec-client-generator-core": "0.61.0",
+    "@typespec/http-client-csharp": "1.0.0-alpha.20251020.2",
+    "@typespec/http": "1.5.0",
+    "@typespec/openapi": "1.5.0"
   },
   "devDependencies": {
     "@types/node": "^22.8.1",