Keyboard shortcuts for navigation (Alt + arrow keys) do not work in in-app file browser

[vikasnataraja]

Prerequisites

• [x] I have searched open and closed issues for duplicates.

Describe the bug

The Alt + left_arrow and Alt + right_arrow keys to go back and forth from a folder do not work in the in-app file browser.

To Reproduce

Steps to reproduce the behavior:

1. Go to any app, do something to open the file browser from within the app
2. Click on any of the directories you have
3. Use Alt+left_arrow to go back
4. See error (nothing happens)

Expected behavior

The Alt + left_arrow and Alt + right_arrow keys definitely work in the regular Files app as expected to navigate between directories but should also work in the in-app file browser in a similar fashion.

[jeremypw]

This is a sub-issue of #129 although it could probably be fixed ad hoc in the existing chooser.

[Vuneu]

Ctrl + L used to work in the in-app file browser, now it doesnt.

[jeremypw]

A fix is unlikely to be approved prior to development of the filechooser portal.

[jeremypw]

The file-chooser portal is now done but still only replaces the pathbar in the Gtk.FileChooser (PR to replace the entry has been proposed). Need investigation of adding an eventcontroller to provide some keyboard shortcuts