Fix FileHistory/Blame for files not existing in the working directory

The bad behavior comes from the fact that `TryGetExactPath()`
changes the path to the file system path (if not existing, the path is cleared)

Alternative for gitextensions#6893

GitUI/CommandsDialogs/FormFileHistory.cs

@@ -207,20 +207,13 @@ private void LoadFileHistory()
             {
                 var fileName = FileName;
 
-                // we will need this later to look up proper casing for the file
-                var fullFilePath = _fullPathResolver.Resolve(fileName);
-
-                if (_controller.TryGetExactPath(fullFilePath, out fileName))
-                {
-                    fileName = fileName.Substring(Module.WorkingDir.Length);
-                }
-
                 // Replace windows path separator to Linux path separator.
                 // This is needed to keep the file history working when started from file tree in
                 // browse dialog.
                 FileName = fileName.ToPosixPath();
 
                 var res = (revision: (string)null, path: $" \"{fileName}\"");
+                var fullFilePath = _fullPathResolver.Resolve(fileName);
 
                 if (AppSettings.FollowRenamesInFileHistory && !Directory.Exists(fullFilePath))
                 {

GitUI/GitUICommands.cs

@@ -1703,6 +1703,11 @@ private void RunFileHistoryCommand(IReadOnlyList<string> args)
             // long while there is room left when the workingdir was not in the path.
             string fileHistoryFileName = string.IsNullOrEmpty(Module.WorkingDir) ? args[2] :
                 args[2].Replace(Module.WorkingDir, "").ToPosixPath();
+            var fullFilePath = _fullPathResolver.Resolve(fileHistoryFileName);
+            if (new FormFileHistoryController().TryGetExactPath(fullFilePath, out var exactFileName))
+            {
+                fileHistoryFileName = exactFileName.Substring(Module.WorkingDir.Length);
+            }
 
             StartFileHistoryDialog(null, fileHistoryFileName);
         }