Linux: Fix file picker not launching from disabling core dumps

Core dumps are disabled by default on Linux, but this prevents access to the file picker due to security hardening. To work around this, core dumps are selectively enabled and disabled around the file picker tasks.

src/Ryujinx/UI/ViewModels/ModManagerViewModel.cs

@@ -288,6 +288,8 @@ namespace Ryujinx.Ava.UI.ViewModels
 
         public async void Add()
         {
+            OsUtils.SetCoreDumpable(true);
+
             IReadOnlyList<IStorageFolder> result = await _storageProvider.OpenFolderPickerAsync(new FolderPickerOpenOptions
             {
                 Title = LocaleManager.Instance[LocaleKeys.SelectModDialogTitle],
@@ -298,6 +300,11 @@ namespace Ryujinx.Ava.UI.ViewModels
             {
                 AddMod(new DirectoryInfo(folder.Path.LocalPath));
             }
+
+            if (!Program.CoreDumpArg)
+            {
+                OsUtils.SetCoreDumpable(false);
+            }
         }
 
         public void DeleteAll()