Handle runner not found (#3536)

src/Sdk/RSWebApi/Contracts/BrokerErrorKind.cs

@@ -5,6 +5,7 @@ namespace GitHub.Actions.RunService.WebApi
     [DataContract]
     public class BrokerErrorKind
     {
+        public const string RunnerNotFound = "RunnerNotFound";
         public const string RunnerVersionTooOld = "RunnerVersionTooOld";
     }
 }

src/Sdk/WebApi/WebApi/BrokerHttpClient.cs

@@ -115,6 +115,8 @@ namespace GitHub.Actions.RunService.WebApi
             {
                 switch (brokerError.ErrorKind)
                 {
+                    case BrokerErrorKind.RunnerNotFound:
+                        throw new RunnerNotFoundException(brokerError.Message);
                     case BrokerErrorKind.RunnerVersionTooOld:
                         throw new AccessDeniedException(brokerError.Message)
                         {

src/Sdk/WebApi/WebApi/Exceptions/RunnerNotFoundException.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+using GitHub.Services.Common;
+using GitHub.Services.WebApi;
+
+namespace GitHub.Services.WebApi
+{
+    [Serializable]
+    public sealed class RunnerNotFoundException : Exception
+    {
+        public RunnerNotFoundException()
+            : base()
+        {
+        }
+
+        public RunnerNotFoundException(String message)
+            : base(message)
+        {
+        }
+
+        public RunnerNotFoundException(String message, Exception innerException)
+            : base(message, innerException)
+        {
+        }
+    }
+}