[fix] fix build failure from package vulnerability (#149)

Package 'Tmds.DBus.Protocol' explicitly added as build fails from
transient package usage. `Warning As Error: Package 'Tmds.DBus.Protocol'
0.21.2 has a known high severity vulnerability,
[https://github.com/advisories/GHSA-xrw6-gwf8-vvr9](https://github.com/advisories/GHSA-xrw6-gwf8-vvr9)

File
[JavaToCSharpGui\ViewModels\MainWindowViewModel.cs](https://github.com/paulirwin/JavaToCSharp/blob/master/JavaToCSharpGui/ViewModels/MainWindowViewModel.cs)
Line187 has been changed from 
    `int subStartIndex = dir.FullName.Length;` to 
    `int subStartIndex = dir.FullName.Length - 1;`

- Fixes exception `'startIndex cannot be larger than length of string.
(Parameter 'startIndex')'` thrown on line193, `string jOutPath =
$"{outDirFullName}{jPath[subStartIndex..]}";` when sub directories are
not present or .java files are directly under chosen directory
- Fixes improper directory duplicate creation when sub dirs are present.
Previous result takes `maindir/subdir_one/file_one.java` and creates 
`maindir/maindir_csharp_outputsubdir_one/file_one.java` & 
`maindir/maindir_csharp_output/subdir_one/file_one.java`
        	
current result takes 
`maindir/subdir_one/file_one.java` and cretes only
`maindir/maindir_csharp_output/subdir_one/file_one.java`

Author: thando-ndlovu

JavaToCSharpGui/ViewModels/MainWindowViewModel.cs

@@ -184,13 +184,13 @@ await Task.Run(async () =>
                     outDir.Create();
 
                 string outDirFullName = outDir.FullName;
-                int subStartIndex = dir.FullName.Length;
 
                 foreach (var jFile in FolderInputFiles.Where(static x => x.Directory is not null))
                 {
                     // ! null checked above
                     string jPath = jFile.Directory!.FullName;
-                    string jOutPath = $"{outDirFullName}{jPath[subStartIndex..]}";
+                    string relativePath = Path.GetRelativePath(dir.FullName, jPath);
+                    string jOutPath = Path.Combine(outDirFullName, relativePath);
                     string jOutFileName = Path.GetFileNameWithoutExtension(jFile.Name) + ".cs";
                     string jOutFileFullName = Path.Combine(jOutPath, jOutFileName);