flatpak: Fix flatpak path in launchers

diff --git a/common/flatpak-dir.c b/common/flatpak-dir.c

index eba81fef..134024e2 100644

--- a/common/flatpak-dir.c

+++ b/common/flatpak-dir.c

@@ -7532,8 +7532,13 @@ export_desktop_file (const char         *app,

       g_key_file_remove_key (keyfile, groups[i], "X-GNOME-Bugzilla-ExtraInfoScript", NULL);

       new_exec = g_string_new ("");

-      if ((flatpak = g_getenv ("FLATPAK_BINARY")) == NULL)

-        flatpak = FLATPAK_BINDIR "/flatpak";

+      if (g_str_has_suffix (name, ".service"))

+      {

+        flatpak = "/run/current-system/sw/bin/flatpak";

+      } else {

+        if ((flatpak = g_getenv ("FLATPAK_BINARY")) == NULL)

+          flatpak = "flatpak";

+      }

       g_string_append_printf (new_exec,

                               "%s run --branch=%s --arch=%s",

@@ -8867,7 +8872,7 @@ flatpak_dir_deploy (FlatpakDir          *self,

                                        error))

         return FALSE;

       if ((flatpak = g_getenv ("FLATPAK_BINARY")) == NULL)

-        flatpak = FLATPAK_BINDIR "/flatpak";

+        flatpak = "flatpak";

       bin_data = g_strdup_printf ("#!/bin/sh\nexec %s run --branch=%s --arch=%s %s \"$@\"\n",

                                   flatpak, escaped_branch, escaped_arch, escaped_app);

    # https://github.com/NixOS/nixpkgs/issues/53441

    ./unset-env-vars.patch

    # Use flatpak from PATH to avoid references to `/nix/store` in `/desktop` files.

    # Applications containing `DBusActivatable` entries should be able to find the flatpak binary.

    # https://github.com/NixOS/nixpkgs/issues/138956

    ./binary-path.patch

    # The icon validator needs to access the gdk-pixbuf loaders in the Nix store

    # and cannot bind FHS paths since those are not available on NixOS.

    finalAttrs.passthru.icon-validator-patch

    PATH=${lib.makeBinPath [vsc-py]}:$PATH patchShebangs --build subprojects/variant-schema-compiler/variant-schema-compiler

  '';

  preFixup = ''

    gappsWrapperArgs+=(

      # Use flatpak from PATH in exported assets (e.g. desktop files).

      --set FLATPAK_BINARY flatpak

    )

  '';

  passthru = {

    icon-validator-patch = substituteAll {

      src = ./fix-icon-validation.patch;