Go: update user settings fields (#14918)

### What problem does this PR solve?

update user settings fields

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

internal/service/user.go

@@ -774,15 +774,19 @@ func (s *UserService) UpdateUserSettings(user *entity.User, req *UpdateSettingsR
 	if req.Avatar != nil {
 		// In Go version, avatar might be stored differently
 		// For now, just update if field exists
+		user.Avatar = req.Avatar
 	}
 	if req.Language != nil {
 		// Store language preference
+		user.Language = req.Language
 	}
 	if req.ColorSchema != nil {
 		// Store color schema preference
+		user.ColorSchema = req.ColorSchema
 	}
 	if req.Timezone != nil {
 		// Store timezone preference
+		user.Timezone = req.Timezone
 	}
 
 	// Save updated user