sway: do not use pkgs.sway when cfg.package = null

[amarshall]

Description

• Implicitly disable checkConfig when cfg.package = null as we don’t
  have any exe to use for the check
• Implicitly disable swaymsg reload on activation, since we have no
  exe to use for running it

See #5307

Checklist

Need to think about if there is a good test to write for this…I did run existing Sway tests and all OK.

• Change is backwards compatible.

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Maintainer CC

[ElysaSrc]

Why couldn't we use the osConfig to get the value ?
Locally, to keep both features I've done this:

{
  config,
  lib,
  pkgs,
  customPkgs,
  osConfig,
  ...
}: {
  wayland.windowManager.sway = {
    enable = true;
    package = osConfig.programs.sway.package;
    extraSessionCommands = osConfig.programs.sway.extraSessionCommands;
    # ...
  };
};

[amarshall]

IMO, that should be something the user decides to do themselves, not something implicit in the default config. There’s also no precedent for consuming osConfig in HM.

[ElysaSrc]

IMO, that should be something the user decides to do themselves, not something implicit in the default config. There’s also no precedent for consuming osConfig in HM.

I was suggesting it because the documentation says:

Sway package to use. Will override the options ‘wrapperFeatures’, ‘extraSessionCommands’, and ‘extraOptions’. Set to null to not add any Sway package to your path. This should be done if you want to use the NixOS Sway module to install Sway.

But I do understand why we shouldn't consume it then.

I haven't had time to check the PR, I'll check it later. For now, I just use osConfig.