fix(ModValidate):未检查路径是否存在

Plain Craft Launcher 2/Modules/Base/ModValidate.vb

@@ -216,6 +216,8 @@ Public Class ValidateFolderName
     End Sub
     Public Overrides Function Validate(Str As String) As String
         Try
+            '检查是否已存在
+            If Not Str = "" AndAlso Directory.Exists($"{Path}\{Str}") Then Return "指定的名称已存在"
             '检查是否为空
             Dim LengthCheck As String = New ValidateNullOrWhiteSpace().Validate(Str)
             If Not LengthCheck = "" Then Return LengthCheck