Validate normal TQ on sticky poll (#5488)

## What changed?
Validate normal TQ on sticky poll

## Why?
On sticky poll, we fetch normal TQ's UserData. So an invalid normal TQ
on a sticky queue would still trigger a load for the invalid normal
queue.

## How did you test it?
Manual test with invalid TQ.

## Potential risks
<!-- Assuming the worst case, what can be broken when deploying this
change to production? -->

## Documentation
<!-- Have you made sure this change doesn't falsify anything currently
stated in `docs/`? If significant
new behavior is added, have you described that in `docs/`? -->

## Is hotfix candidate?
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service/frontend/workflow_handler.go

@@ -4314,6 +4314,11 @@ func (wh *WorkflowHandler) validateTaskQueue(t *taskqueuepb.TaskQueue) error {
 	if err := common.ValidateUTF8String("TaskQueue", t.GetName()); err != nil {
 		return err
 	}
+	if t.GetKind() == enumspb.TASK_QUEUE_KIND_STICKY {
+		if err := common.ValidateUTF8String("TaskQueue", t.GetNormalName()); err != nil {
+			return err
+		}
+	}
 
 	enums.SetDefaultTaskQueueKind(&t.Kind)
 	return nil

service/frontend/workflow_handler_test.go

@@ -2955,3 +2955,21 @@ func (s *workflowHandlerSuite) Test_DeleteWorkflowExecution() {
 	s.NoError(err)
 	s.NotNil(resp)
 }
+
+func (s *workflowHandlerSuite) Test_ValidateTaskQueue() {
+	wh := s.getWorkflowHandler(s.newConfig())
+
+	tq := taskqueuepb.TaskQueue{Name: "\x87\x01"}
+	err := wh.validateTaskQueue(&tq)
+	s.Error(err)
+	s.Contains(err.Error(), "is not a valid UTF-8 string")
+
+	tq = taskqueuepb.TaskQueue{Name: "valid-tq-name"}
+	err = wh.validateTaskQueue(&tq)
+	s.NoError(err)
+
+	tq = taskqueuepb.TaskQueue{Name: "valid-tq-name", NormalName: "\x87\x01", Kind: enumspb.TASK_QUEUE_KIND_STICKY}
+	err = wh.validateTaskQueue(&tq)
+	s.Error(err)
+	s.Contains(err.Error(), "is not a valid UTF-8 string")
+}