Remove is_grabbed check for changing active window

When clicking outside of the popup grab, the click does go through if
the popup is dismissed. This makes the active window change go through
too.

src/input.rs

@@ -806,7 +806,7 @@ impl State {
 
         let button_state = event.state();
 
-        if ButtonState::Pressed == button_state && !pointer.is_grabbed() {
+        if ButtonState::Pressed == button_state {
             if let Some(window) = self.niri.window_under_cursor() {
                 let window = window.clone();
                 self.niri.layout.activate_window(&window);