staruml: No GSettings Schemas are installed on the system

[Infinidoge]

Describe the bug

When attempting to do various actions in Staruml, such as export to PDF, the application crashes with the message "No GSettings schemas are installed on the system."

Reading into the NixOS wiki, I tried to follow the steps outlined here: https://nixos.wiki/wiki/Packaging/Quirks_and_Caveats for the GLib GIO message, however it was unsuccessful. (Added wrapGAppsHook to the nativeBuildInputs, trying to build led to an "invalid ELF header" error.)

Steps To Reproduce

Steps to reproduce the behavior:

1. Install staruml on a non-GNOME system (using nix-shell -p staruml in this case)
2. Run staruml using staruml
3. Attempt to export a diagram to PDF
4. Experience crash

Expected behavior

The application should successfully export to PDF

Screenshots

Notify maintainers

@siraben (Though not officially listed as a maintainer, saw you were involved with maintaining the package in the past).

Metadata

 - system: `"x86_64-linux"`
 - host os: `Linux 5.16.4, NixOS, 22.05 (Quokka)`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.7.0pre20220127_558c4ee`
 - nixpkgs: `/nix/store/pi099gbqmvjaqk6d77c9r9g08mm70w8b-source`

My Nixpkgs revision is c5051e2b5fe9fab43a64f0e0d06b62c81a890b90, if I've read my flake.lock correctly.