client: only report error when EnableTSOFollowerProxy is true in ms mode (#9130) (#9803)

close #9129

Signed-off-by: ti-chi-bot <ti-community-prow-bot@tidb.io>
Signed-off-by: nolouch <nolouch@gmail.com>
Signed-off-by: Ryan Leung <rleungx@gmail.com>

Co-authored-by: ShuNing <nolouch@gmail.com>
Co-authored-by: nolouch <nolouch@gmail.com>
Co-authored-by: Ryan Leung <rleungx@gmail.com>

Author: 3 people

client/client.go

@@ -640,13 +640,13 @@ func (c *client) UpdateOption(option DynamicOption, value any) error {
 			return err
 		}
 	case EnableTSOFollowerProxy:
-		if c.getServiceMode() != pdpb.ServiceMode_PD_SVC_MODE {
-			return errors.New("[pd] tso follower proxy is only supported in PD service mode")
-		}
 		enable, ok := value.(bool)
 		if !ok {
 			return errors.New("[pd] invalid value type for EnableTSOFollowerProxy option, it should be bool")
 		}
+		if c.getServiceMode() != pdpb.ServiceMode_PD_SVC_MODE && enable {
+			return errors.New("[pd] tso follower proxy is only supported in PD service mode")
+		}
 		c.option.setEnableTSOFollowerProxy(enable)
 	case EnableFollowerHandle:
 		enable, ok := value.(bool)