Disable GNOME Evolution sandboxing to enable printing

[l0b0]

Describe the bug
Based on this and this, it would be good if we temporarily change the Evolution .desktop file to contain env WEBKIT_FORCE_SANDBOX=0 at the start of the Exec= command.

To Reproduce
Steps to reproduce the behavior:

1. Launch Evolution from the desktop shortcut installed by NixOS
2. Try to print, either to file or to a printer
3. Get a misleading error message about a missing file or a printer which can't be found

Expected behavior
Evolution should print.

Metadata

$ nix-shell -p nix-info --run "nix-info -m"
these paths will be fetched (0.05 MiB download, 0.28 MiB unpacked):
  /nix/store/wzach25vwapl3sa6f7gylqank3jhhsin-bash-interactive-4.4-p23-dev
copying path '/nix/store/wzach25vwapl3sa6f7gylqank3jhhsin-bash-interactive-4.4-p23-dev' from 'https://cache.nixos.org'...
 - system: `"x86_64-linux"`
 - host os: `Linux 5.10.50, NixOS, 21.05.1590.63ee5cd99a2 (Okapi)`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.3.12`
 - channels(root): `"nixos-21.05.1590.63ee5cd99a2"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

Maintainer information:

# a list of nixpkgs attributes affected by the problem
attribute:
# a list of nixos modules affected by the problem
module: pkgs.evolution

[jtojnar]

This is done in GNOME 41 (#139144):

https://gitlab.gnome.org/GNOME/evolution/-/blob/3.42.0/NEWS#L154