nixosTests.gnome: Fix tests for 44

1. Launching an app externally (like we do in tests) does not dismiss the GNOME Shell’s Activities view opened on log-in.
2. Activities view grabs input so that user can type to search.
3. Due to a regression in Mutter 44, a window focus is not acquired when Shell grabs input
   https://gitlab.gnome.org/GNOME/mutter/-/commit/3ac82a58c51a5c8db6b49e89a1232f99c79644cc

As a result, trying to determine the WMClass would throw:

    TypeError: global.display.focus_window is null

Let’s dismiss the Activities view with Escape key as a workaround.

nixos/tests/gnome-xorg.nix

@@ -82,6 +82,9 @@ import ./make-test-python.nix ({ pkgs, lib, ...} : {
           )
 
       with subtest("Open Console"):
+          # Close the Activities view so that Shell can correctly track the focused window.
+          machine.send_key("esc")
+
           machine.succeed(
               "${launchConsole}"
           )

nixos/tests/gnome.nix

@@ -79,6 +79,9 @@ import ./make-test-python.nix ({ pkgs, lib, ...} : {
           )
 
       with subtest("Open Console"):
+          # Close the Activities view so that Shell can correctly track the focused window.
+          machine.send_key("esc")
+
           machine.succeed(
               "${launchConsole}"
           )