[feat] add Condition.IsAlwaysRight func

orm.go

@@ -152,6 +152,7 @@ type Condition interface {
 	Type() ConditionType
 	IsEmpty() bool
 	IsNotEmpty() bool
+	IsAlwaysRight() bool
 	ToSql(Model) db.Expression
 	AppendTo(Condition)
 	SetExpr(ConditionExpr) Condition