### 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.
if (theme_icon_override.has(dname)) {
				theme_icon_override[dname]->disconnect("changed", callable_mp(this, &Window::_notify_theme_override_changed));
			}
			theme_icon_override.erase(dname);
			_notify_theme_override_changed();
		} else if (name.begins_with("theme_override_styles/")) {
			String dname = name.get_slicec('/', 1);
			if (theme_style_override.has(dname)) {
				theme_style_override[dname]->disconnect("changed", callable_mp(this, &Window::_notify_theme_override_changed));
			}
			theme_style_override.erase(dname);
			_notify_theme_override_changed();
		} else if (name.begins_with("theme_override_fonts/")) {
			String dname = name.get_slicec('/', 1);
			if (theme_font_override.has(dname)) {
				theme_font_override[dname]->disconnect("changed", callable_mp(this, &Window::_notify_theme_override_changed));
			}
			theme_font_override.erase(dname);
			_notify_theme_override_changed();
		} else if (name.begins_with("theme_override_font_sizes/")) {
			String dname = name.get_slicec('/', 1);
			theme_font_size_override.erase(dname);
			_notify_theme_override_changed();
		} else if (name.begins_with("theme_override_colors/")) {
			String dname = name.get_slicec('/', 1);
			theme_color_override.erase(dname);
			_notify_theme_override_changed();
		} else if (name.begins_with("theme_override_constants/")) {
			String dname = name.get_slicec('/', 1);
			theme_constant_override.erase(dname);