Running any command through the flathub binary fails

[Jacek Wielemborek]

Steps to reproduce:

1. Run flatpak run fyi.zoey.Boop-GTK
2. Enter "dupa"
3. Press ctrl+shift+p
4. Select any of the options, e.g. the first one
5. Observe the following error (with backtrace enabled):

The application panicked (crashed).
Message:  called `Result::unwrap()` on an `Err` value: "Add Slashes"
Location: src/ui/command_pallete.rs:278

  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ BACKTRACE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
   1: g_closure_invoke<unknown>
      at <unknown source file>:<unknown line>
   2: g_signal_emit_valist<unknown>
      at <unknown source file>:<unknown line>
   3: g_signal_emit<unknown>
      at <unknown source file>:<unknown line>
   4: gtk_main_do_event<unknown>
      at <unknown source file>:<unknown line>
   5: g_main_context_dispatch<unknown>
      at <unknown source file>:<unknown line>
   6: g_main_context_iteration<unknown>
      at <unknown source file>:<unknown line>
   7: g_application_run<unknown>
      at <unknown source file>:<unknown line>
   8: __libc_start_main<unknown>
      at <unknown source file>:<unknown line>

Run with COLORBT_SHOW_HIDDEN=1 environment variable to disable frame filtering.

> lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04.3 LTS
Release:        20.04
Codename:       focal

I'm using a combination of xfce and i3.