hermes:phoebe: Remove deprecated plasma-browser-integration for firefox

There is new nativeMassagingHosts option being suggested instead, but
the thing is, plasma-browser-integration for firefox is already enabled
by plasma-desktop itself in nixpkgs. So when it is enabled again by user
config, there is a conflict and the config does not build.

Still need to see if this allows user applicable config instead

hosts/hermes/home.nix

@@ -28,7 +28,6 @@
     digikam
     okular
     kcalc
-    firefox-wayland
     ark # munging archives
     unrar # So ark can open .rar files
     spectacle

hosts/phoebe/home.nix

@@ -21,7 +21,6 @@
     # apps
     vlc
     strawberry
-    firefox-wayland
     nheko
 
     # utilities

modules/plasma-desktop.nix

@@ -32,6 +32,10 @@
   programs = {
     xwayland.enable = true;
     kdeconnect.enable = true;
+    firefox = {
+      enable = true;
+      preferencesStatus = "user";
+    };
   };
 
   qt.platformTheme = "kde";
@@ -45,13 +49,6 @@
     fi
   '';
 
-  nixpkgs = {
-    config = {
-      # Enable plasma integration
-      firefox.enablePlasmaBrowserIntegration = true;
-    };
-  };
-
   environment = {
     plasma5.excludePackages = with pkgs; [
       plasma5Packages.oxygen