Return ScmMethodProvider when building operation methods (#54140)

* debug etag issue.

* write console debug info

* WIP

* regen after rebase.

* regen

* regen

* add doc for if-match parameter.

Author: haiyuazhang

eng/packages/http-client-csharp-mgmt/generator/Azure.Generator.Management/src/Providers/OperationMethodProviders/ResourceOperationMethodProvider.cs

@@ -133,10 +133,14 @@ protected virtual CSharpType BuildReturnType()
 
         public static implicit operator MethodProvider(ResourceOperationMethodProvider resourceOperationMethodProvider)
         {
-            var methodProvider = new MethodProvider(
+            var methodProvider = new ScmMethodProvider(
                 resourceOperationMethodProvider._signature,
                 resourceOperationMethodProvider._bodyStatements,
-                resourceOperationMethodProvider._enclosingType);
+                resourceOperationMethodProvider._enclosingType,
+                ScmMethodKind.Convenience,
+                null,
+                null,
+                resourceOperationMethodProvider._serviceMethod);
 
             // Add enhanced XML documentation with structured tags
             ResourceHelpers.BuildEnhancedXmlDocs(

eng/packages/http-client-csharp-mgmt/generator/TestProjects/Local/Mgmt-TypeSpec/databox.tsp

@@ -46,6 +46,13 @@ interface JobResources {
   update is ArmCustomPatchAsync<
     JobResource,
     PatchModel = JobResourceUpdateParameter,
+    Parameters = {
+      /**
+       * Defines the If-Match condition. The patch will be performed only if the ETag of the job on the server matches this value.
+       */
+      @header("If-Match")
+      `If-Match`?: string;
+    }
   >;
 }