### Godot version

4.x

### System information

Windows 10

### Issue description

The `Search Result` panel is not correctly updated when changing the theme.

https://user-images.githubusercontent.com/66004280/208964493-d0423b78-3418-44c9-95ed-822fd34c4720.mp4



### Steps to reproduce

1. Search something
2. Change the theme

### Minimal reproduction project

--
ADD_SIGNAL(MethodInfo(SIGNAL_RESULT_FOUND,
			PropertyInfo(Variant::STRING, "path"),
			PropertyInfo(Variant::INT, "line_number"),
			PropertyInfo(Variant::INT, "begin"),
			PropertyInfo(Variant::INT, "end"),
			PropertyInfo(Variant::STRING, "text")));
	ADD_SIGNAL(MethodInfo(SIGNAL_FINISHED));
}
const char *FindInFilesDialog::SIGNAL_FIND_REQUESTED = "find_requested";
const char *FindInFilesDialog::SIGNAL_REPLACE_REQUESTED = "replace_requested";
FindInFilesDialog::FindInFilesDialog() {
	set_min_size(Size2(500 * EDSCALE, 0));
	set_title(TTR("Find in Files"));
	VBoxContainer *vbc = memnew(VBoxContainer);
	vbc->set_anchor_and_offset(SIDE_LEFT, Control::ANCHOR_BEGIN, 8 * EDSCALE);
	vbc->set_anchor_and_offset(SIDE_TOP, Control::ANCHOR_BEGIN, 8 * EDSCALE);
	vbc->set_anchor_and_offset(SIDE_RIGHT, Control::ANCHOR_END, -8 * EDSCALE);
	vbc->set_anchor_and_offset(SIDE_BOTTOM, Control::ANCHOR_END, -8 * EDSCALE);
	add_child(vbc);
	GridContainer *gc = memnew(GridContainer);
	gc->set_columns(2);
	vbc->add_child(gc);
	Label *find_label = memnew(Label);
	find_label->set_text(TTR("Find:"));
	gc->add_child(find_label);
	_search_text_line_edit = memnew(LineEdit);