gradience: add glib-networking to buildInputs

The Gradience supports downloading community presets which are located
at GitHub using HTTPS:

af81166e2b/gradience/backend/globals.py (L31-L34)

However glib-networking is required for TLS support.

This patch adds this missing dependency to fix downloading Gradience
presets.

pkgs/applications/misc/gradience/default.nix

@@ -6,6 +6,7 @@
 , ninja
 , pkg-config
 , glib
+, glib-networking
 , desktop-file-utils
 , gettext
 , librsvg
@@ -50,6 +51,7 @@ python3Packages.buildPythonApplication rec {
   ];
 
   buildInputs = [
+    glib-networking
     libadwaita
     libportal
     libportal-gtk4