Fix incorrect hash calculation for files in nested directories (#628)

* Fix path to additional files in inner directories for hash calc

Example path: Game Options\AI\No Change.ini

* workaround for net48: substring

DXMainClient/Online/FileHashCalculator.cs

@@ -151,7 +151,7 @@ public void CalculateHashes()
             {
                 if (path.Exists)
                 {
-                    foreach (string filename in path.EnumerateFiles("*", SearchOption.AllDirectories).Select(s => s.Name))
+                    foreach (string filename in path.EnumerateFiles("*", SearchOption.AllDirectories).Select(s => s.FullName.Substring(path.FullName.Length)))
                     {
                         string fileRelativePath = SafePath.CombineFilePath(path.Name, filename);
                         string fileFullPath = SafePath.CombineFilePath(path.FullName, filename);