Do not generate clean block in proxy function when the feature is disabled (#17112)

src/System.Management.Automation/engine/CommandMetadata.cs

@@ -864,6 +864,15 @@ dynamicparam
 ", GetDynamicParamBlock());
             }
 
+            string cleanBlock = string.Empty;
+            if (ExperimentalFeature.IsEnabled(ExperimentalFeature.PSCleanBlockFeatureName))
+            {
+                cleanBlock = string.Format(CultureInfo.InvariantCulture, @"
+clean
+{{{0}}}
+", GetCleanBlock());
+            }
+
             string result = string.Format(CultureInfo.InvariantCulture, @"{0}
 param({1})
 
@@ -875,9 +884,7 @@ process
 
 end
 {{{5}}}
-
-clean
-{{{6}}}
+{6}
 <#
 {7}
 #>
@@ -888,7 +895,7 @@ clean
                 GetBeginBlock(),
                 GetProcessBlock(),
                 GetEndBlock(),
-                GetCleanBlock(),
+                cleanBlock,
                 CodeGeneration.EscapeBlockCommentContent(helpComment));
 
             return result;