element-desktop: use electron-bin instead of from-source electron

hosts/common/programs/element-desktop.nix

@@ -4,9 +4,14 @@
 #     - <https://github.com/vector-im/element-desktop/issues/1029#issuecomment-1632688224>
 #   - `rm -rf ~/.config/Element/GPUCache`
 #     - <https://github.com/NixOS/nixpkgs/issues/244486>
-{ ... }:
+{ pkgs, ... }:
 {
   sane.programs.element-desktop = {
+    package = pkgs.element-desktop.override {
+      # use pre-build electron because otherwise it takes 4 hrs to build from source.
+      electron = pkgs.electron-bin;
+    };
+
     # creds/session keys, etc
     persist.byStore.private = [ ".config/Element" ];