### Godot version

4.1.dev (dc625bcbfc5b587ba8867481ee7a1f6a567c25d0)

### System information

Mageia 9, Linux

### Issue description

When importing a project in current `master`, the following error is raised for each asset that gets imported:
```
Attempting to parent and popup a dialog that already has a parent.
```

It seems to be raised once per asset, caused by the progress dialog.

CC @bruvzg

### Steps to reproduce

- Import a new project in Godot that contains importable assets, e.g. https://github.com/RPicster/godot4-demo-desert-light

### Minimal reproduction project

See above.
main_vbox->add_theme_constant_override("separation", 8 * EDSCALE);
	title_bar = memnew(EditorTitleBar);
	main_vbox->add_child(title_bar);
	left_l_hsplit = memnew(HSplitContainer);
	main_vbox->add_child(left_l_hsplit);
	left_l_hsplit->set_v_size_flags(Control::SIZE_EXPAND_FILL);
	left_l_vsplit = memnew(VSplitContainer);
	left_l_hsplit->add_child(left_l_vsplit);
	dock_slot[DOCK_SLOT_LEFT_UL] = memnew(TabContainer);
	left_l_vsplit->add_child(dock_slot[DOCK_SLOT_LEFT_UL]);
	dock_slot[DOCK_SLOT_LEFT_BL] = memnew(TabContainer);
	left_l_vsplit->add_child(dock_slot[DOCK_SLOT_LEFT_BL]);
	left_r_hsplit = memnew(HSplitContainer);
	left_l_hsplit->add_child(left_r_hsplit);
	left_r_vsplit = memnew(VSplitContainer);
	left_r_hsplit->add_child(left_r_vsplit);
	dock_slot[DOCK_SLOT_LEFT_UR] = memnew(TabContainer);
	left_r_vsplit->add_child(dock_slot[DOCK_SLOT_LEFT_UR]);
	dock_slot[DOCK_SLOT_LEFT_BR] = memnew(TabContainer);
	left_r_vsplit->add_child(dock_slot[DOCK_SLOT_LEFT_BR]);
	main_hsplit = memnew(HSplitContainer);
	left_r_hsplit->add_child(main_hsplit);
	VBoxContainer *center_vb = memnew(VBoxContainer);
	main_hsplit->add_child(center_vb);
	center_vb->set_h_size_flags(Control::SIZE_EXPAND_FILL);
	center_split = memnew(VSplitContainer);
	center_split->set_v_size_flags(Control::SIZE_EXPAND_FILL);
	center_split->set_collapsed(false);
	center_vb->add_child(center_split);
	right_hsplit = memnew(HSplitContainer);