firefox-bin: remove GConf dependency

It is only optionally dlopened by crash reporter to try to get system proxy settings
but no system stores proxy in GConf these days so it is completely useless.

https://github.com/mozilla/gecko-dev/blob/97c590ed5532a7b382b5b8500c109de8f1d831e3/toolkit/crashreporter/client/crashreporter_gtk_common.cpp#L121-L122

pkgs/applications/networking/browsers/firefox-bin/default.nix

@@ -8,7 +8,6 @@
 , dbus
 , fontconfig
 , freetype
-, gconf
 , gdk-pixbuf
 , glib
 , glibc
@@ -101,7 +100,6 @@ stdenv.mkDerivation {
       dbus
       fontconfig
       freetype
-      gconf
       gdk-pixbuf
       glib
       glibc

pkgs/top-level/all-packages.nix

@@ -19760,7 +19760,6 @@ in
   firefox-bin-unwrapped = callPackage ../applications/networking/browsers/firefox-bin {
     channel = "release";
     generated = import ../applications/networking/browsers/firefox-bin/release_sources.nix;
-    gconf = pkgs.gnome2.GConf;
   };
 
   firefox-bin = wrapFirefox firefox-bin-unwrapped {
@@ -19772,7 +19771,6 @@ in
   firefox-beta-bin-unwrapped = firefox-bin-unwrapped.override {
     channel = "beta";
     generated = import ../applications/networking/browsers/firefox-bin/beta_sources.nix;
-    gconf = pkgs.gnome2.GConf;
   };
 
   firefox-beta-bin = res.wrapFirefox firefox-beta-bin-unwrapped {
@@ -19784,7 +19782,6 @@ in
   firefox-devedition-bin-unwrapped = callPackage ../applications/networking/browsers/firefox-bin {
     channel = "devedition";
     generated = import ../applications/networking/browsers/firefox-bin/devedition_sources.nix;
-    gconf = pkgs.gnome2.GConf;
   };
 
   firefox-devedition-bin = res.wrapFirefox firefox-devedition-bin-unwrapped {