Fix error that did not ignore fields with no ksql tags on QueryOne

The original attempt of fixing this problem was on commit:

e970a3546a

ksql.go

@@ -1130,6 +1130,11 @@ func buildSelectQueryForPlainStructs(
 ) string {
 	var fields []string
 	for i := 0; i < structType.NumField(); i++ {
+		structInfo := info.ByIndex(i)
+		if !structInfo.Valid {
+			continue
+		}
+
 		fields = append(fields, dialect.Escape(info.ByIndex(i).Name))
 	}
 

ksql_test.go

@@ -21,6 +21,9 @@ type User struct {
 	Age  int    `ksql:"age"`
 
 	Address Address `ksql:"address,json"`
+
+	// This attr has no ksql tag, thus, it should be ignored:
+	AttrThatShouldBeIgnored string
 }
 
 var UsersTable = NewTable("users")