Update AutoRest C# version to 3.0.0-beta.20250426.1 (Azure#49666)

* Update Generator Version 3.0.0-beta.20250426.1

* Update SDK codes ma_pr_4

* revert unstable regen

---------

Co-authored-by: Wei Hu <[email protected]>

Author: azure-sdk

eng/Packages.Data.props

@@ -277,7 +277,7 @@
     All should have PrivateAssets="All" set so they don't become package dependencies
   -->
   <ItemGroup>
-    <PackageReference Update="Microsoft.Azure.AutoRest.CSharp" Version="3.0.0-beta.20250422.1" PrivateAssets="All" />
+    <PackageReference Update="Microsoft.Azure.AutoRest.CSharp" Version="3.0.0-beta.20250426.1" PrivateAssets="All" />
     <PackageReference Update="Azure.ClientSdk.Analyzers" Version="0.1.1-dev.20250310.1" PrivateAssets="All" />
     <PackageReference Update="coverlet.collector" Version="3.2.0" PrivateAssets="All" />
     <!-- Note: Upgrading the .NET SDK version needs to be synchronized with the autorest.csharp repository -->

eng/emitter-package-lock.json

@@ -1,7 +1,7 @@
 {
   "main": "dist/src/index.js",
   "dependencies": {
-    "@azure-tools/typespec-csharp": "0.2.0-beta.20250422.1"
+    "@azure-tools/typespec-csharp": "0.2.0-beta.20250426.1"
   },
   "devDependencies": {
     "@azure-tools/typespec-autorest": "0.54.0",