"Show Sketch folder" points to temp directory when opened via File > Sketchbook > Sketch_name

[ubidefeo]

Describe the bug
If I need to add files to my Sketch I need quickly find the folder and see my files,
but the Sketch > Show Sketch Folder opens the temporary directory, hence every change is lost.
i.e.: the Recent submenu does not update with the open Sketch

This only seems to happen when Sketch is open via File > Sketchbook.
The same file reports the correct absolute path if open via File > Open

To Reproduce
Steps to reproduce the behavior:

1. Open a pre-existing Sketch (or save a new one)
2. Click on Sketch > Show Sketch Folder
3. Look at the containing tree
4. You will see that you got directed to the temporary folder, not to the one inside the Sketchbook
5. This seems to also prevent the **File > Open Recent ** not to have updated content even after a restart

Expected behavior
Pointing to the content of my Sketch inside the Sketchbook folder and having the File > Open Recent correctly show the file I last opened.

Screenshots

Desktop (please complete the following information):

• OS: Mac OS 11.2.3 Big Sur
• Version: 2.0.0-beta.4-nightly.20210402

[silvanocerza]

I investigated a bit and turns out that this bug has been introduced by c64ac48 and PR #198.