Update Http.cs (#611)

tools/code/common/Http.cs

@@ -385,6 +385,7 @@ public class CommonRetryPolicy : RetryPolicy
                 {
                     ({ Response.Status: 422 or 409 }, _) when HasManagementApiRequestFailedError(message.Response) => true,
                     ({ Response.Status: 412 }, _) => true,
+                    ({ Response.Status: 429 }, _) => true,
                     _ => false
                 };
         }
@@ -430,4 +431,4 @@ public class TelemetryPolicy(Version version) : HttpPipelinePolicy
 
         await ProcessNextAsync(message, pipeline);
     }
-}
+}