Use MOUSE_FILTER_PASS for all containers (but PanelContainer)

Containers are meant to forward mouse input to their the Controls
they contain.

PanelContainer has a visible Panel stylebox, so it still defaults
to STOP.

Fixes #34933.

scene/gui/grid_container.cpp

@@ -247,7 +247,5 @@ Size2 GridContainer::get_minimum_size() const {
 }
 
 GridContainer::GridContainer() {
-
-	set_mouse_filter(MOUSE_FILTER_PASS);
 	columns = 1;
 }