[history] more cautious in deciding domain state to make decisions on…

… dropping queued tasks (#5164)

What changed?

When domain cache returned entity not found error, don't drop queued tasks to be more conservative.

Why?

In cases when the cache is dubious, we shouldn't drop the queued tasks.

service/history/queue/task_allocator.go

@@ -196,10 +196,7 @@ func (t *taskAllocatorImpl) Unlock() {
 func isDomainNotRegistered(shard shard.Context, domainID string) (bool, error) {
 	domainEntry, err := shard.GetDomainCache().GetDomainByID(domainID)
 	if err != nil {
-		if _, ok := err.(*types.EntityNotExistsError); ok {
-			return true, nil
-		}
-		// unexpected error in finding a domain
+		// error in finding a domain
 		return false, err
 	}
 	info := domainEntry.GetInfo()