Task Queue Validation Change (#6470)

## What changed?
<!-- Describe what has changed in this PR -->
Only validate sticky queue normal name if it is set

## Why?
<!-- Tell your future self why have you made these changes -->
Compatibility with older SDKs

## How did you test it?
<!-- How have you verified this change? Tested locally? Added a unit
test? Checked in staging env? -->
Unit test

## 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?
<!-- Is this PR a hotfix candidate or does it require a notification to
be sent to the broader community? (Yes/No) -->

common/tqid/task_queue_validator.go

@@ -72,8 +72,11 @@ func NormalizeAndValidate(
 	}
 
 	if taskQueue.GetKind() == enumspb.TASK_QUEUE_KIND_STICKY {
-		if err := Validate(taskQueue.GetNormalName(), maxIDLengthLimit); err != nil {
-			return err
+		normalName := taskQueue.GetNormalName()
+		if normalName != "" {
+			if err := Validate(normalName, maxIDLengthLimit); err != nil {
+				return err
+			}
 		}
 	}
 

common/tqid/task_queue_validator_test.go

@@ -27,6 +27,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+
 	enumspb "go.temporal.io/api/enums/v1"
 	taskqueuepb "go.temporal.io/api/taskqueue/v1"
 )
@@ -128,14 +129,6 @@ func TestNormalizeAndValidate(t *testing.T) {
 			expectedError:    "taskQueue \"\\xff\\xfe\\xfd\" is not a valid UTF-8 string",
 			expectedKind:     enumspb.TASK_QUEUE_KIND_STICKY,
 		},
-		{
-			name:             "Sticky queue with empty normal name",
-			taskQueue:        &taskqueuepb.TaskQueue{Name: "sticky", Kind: enumspb.TASK_QUEUE_KIND_STICKY, NormalName: ""},
-			defaultVal:       "",
-			maxIDLengthLimit: 100,
-			expectedError:    "taskQueue is not set",
-			expectedKind:     enumspb.TASK_QUEUE_KIND_STICKY,
-		},
 		{
 			name:             "Non-sticky queue with normal name set",
 			taskQueue:        &taskqueuepb.TaskQueue{Name: "normal", Kind: enumspb.TASK_QUEUE_KIND_NORMAL, NormalName: "should-be-ignored"},