[file browser] "back to starting directory" button does not work

[kswang1029]

Describe the bug
The "back to starting directory" button does not work in the file browser dialog.

When it is clicked, an error is returned: "Error loading file list for directory"

To Reproduce
Steps to reproduce the behavior:

1. launch CARTA
2. click the button to see the error

Expected behavior
When the button is clicked, it should navigate back to the starting directory.

Platform info (please complete the following information):

• OS [e.g. macOS Monterey]: macOS Ventura
• Browser [e.g. chrome, safari, electron app]: chrome, electron app
• Browser version [e.g. 22]: 122
• Backend branch [e.g. dev, v3b2 release]: dev, v4-stable
• Frontend branch [e.g. dev, v3b2 release]: dev, v4-stable