fix interactive login add (#557)

if you just hit "enter" the loginMethod is `` so this coves that case

Reviewed-on: https://gitea.com/gitea/tea/pulls/557
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Reviewed-by: techknowlogick <techknowlogick@noreply.gitea.com>
Co-authored-by: 6543 <6543@obermui.de>
Co-committed-by: 6543 <6543@obermui.de>

modules/interact/login.go

@@ -49,7 +49,7 @@ func CreateLogin() error {
 	}
 
 	switch loginMethod {
-	case "token":
+	default: // token
 		var hasToken bool
 		promptYN := &survey.Confirm{
 			Message: "Do you have an access token?",