### 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_FIND_REQUESTED));
	ADD_SIGNAL(MethodInfo(SIGNAL_REPLACE_REQUESTED));
}
const char *FindInFilesPanel::SIGNAL_RESULT_SELECTED = "result_selected";
const char *FindInFilesPanel::SIGNAL_FILES_MODIFIED = "files_modified";
FindInFilesPanel::FindInFilesPanel() {
	_finder = memnew(FindInFiles);
	_finder->connect(FindInFiles::SIGNAL_RESULT_FOUND, callable_mp(this, &FindInFilesPanel::_on_result_found));
	_finder->connect(FindInFiles::SIGNAL_FINISHED, callable_mp(this, &FindInFilesPanel::_on_finished));
	add_child(_finder);
	VBoxContainer *vbc = memnew(VBoxContainer);
	vbc->set_anchor_and_offset(SIDE_LEFT, ANCHOR_BEGIN, 0);
	vbc->set_anchor_and_offset(SIDE_TOP, ANCHOR_BEGIN, 0);
	vbc->set_anchor_and_offset(SIDE_RIGHT, ANCHOR_END, 0);
	vbc->set_anchor_and_offset(SIDE_BOTTOM, ANCHOR_END, 0);
	add_child(vbc);
	{
		HBoxContainer *hbc = memnew(HBoxContainer);
		Label *find_label = memnew(Label);
		find_label->set_text(TTR("Find:"));
		hbc->add_child(find_label);
		_search_text_label = memnew(Label);
		_search_text_label->add_theme_font_override("font", EditorNode::get_singleton()->get_gui_base()->get_theme_font(SNAME("source"), SNAME("EditorFonts")));
		_search_text_label->add_theme_font_size_override("font_size", EditorNode::get_singleton()->get_gui_base()->get_theme_font_size(SNAME("source_size"), SNAME("EditorFonts")));
		hbc->add_child(_search_text_label);
		_progress_bar = memnew(ProgressBar);
		_progress_bar->set_h_size_flags(SIZE_EXPAND_FILL);
		_progress_bar->set_v_size_flags(SIZE_SHRINK_CENTER);