firejail.wrappedBinaries having no effect

I have put this in /etc/nixos/configuration.nix, run nixos-rebuild --upgrade switch, and rebooted, but running the command thunderbird and then firejail --list (in another terminal), there are no firejail sandboxes listed.

  programs.firejail.enable = true;
  programs.firejail.wrappedBinaries = {
    thunderbird = {
      executable = "${lib.getBin pkgs.thunderbird}/bin/thunderbird";
      profile = "${pkgs.firejail}/etc/firejail/thunderbird.profile";
    telegram-desktop = {
      executable = "${lib.getBin pkgs.tdesktop}/bin/telegram-desktop";
      profile = "${pkgs.firejail}/etc/firejail/telegram.profile";
    wire-desktop = {
      executable = "${lib.getBin pkgs.wire-desktop}/bin/wire-desktop";
      profile = "${pkgs.firejail}/etc/firejail/wire-desktop.profile";

I also get errors about file collisions:

warning: collision between `/nix/store/jqkyn40x8ax9r5syrsxndw6kvci6n8yl-firejail-wrapped-binaries/bin/wire-desktop' and `/nix/store/r8fklvpjp180n4i7qwfyas9nrazmm9k2-wire-desktop-3.26.2941/bin/wire-desktop'
warning: collision between `/nix/store/jqkyn40x8ax9r5syrsxndw6kvci6n8yl-firejail-wrapped-binaries/bin/telegram-desktop' and `/nix/store/ffjvmxrz865fdfaq7pjkf1vvc1yjh2vz-telegram-desktop-3.1.11/bin/telegram-desktop'

I seem to have two separate problems here, and I don’t know how to resolve either.

The problem turned out to be that I thought I also had to specify the packages in environment.systemPackages, which takes precedence over programs.firejail.wrappedBinaries. (See nixpkgs issue #152852 for full details.)

But there is also a separate problem where Wire simply will not run under firejail, and there is a separete issue for this.