Added execution context error

This will make a failed health check more visible in the UI without disrupting the execution of the program.

src/Runner.Worker/ContainerOperationProvider.cs

@@ -431,6 +431,7 @@ namespace GitHub.Runner.Worker
             {
                 executionContext.Output($"##[group]Container {container.ContainerImage} failed healthchecks, printing logs:");
                 await _dockerManager.DockerLogs(context: executionContext, containerId: container.ContainerId);
+                executionContext.Error($"Failed to initialize container {container.ContainerImage}");
                 executionContext.Output("##[endgroup]");
             }
         }