### Godot version

v4.0.beta.custom_build [13f0158]

### System information

Windows 10

### Issue description

When doing operations (`begin_complex_operation` and `end_complex_operation`) with multiple selections in TextEdit, some of these selections don't revert upon undo. This behavior is affects some of script editor's operations, like duplicate selection and delete lines.

### Steps to reproduce

Open script editor, make multiple selections. Keep in mind what you have selected. Do duplicate selection (ctrl+shift+D). Undo (ctrl+Z). Compare the result to what you remember.

### Minimal reproduction project

N/A
for (int i = 0; i < carets.size(); i++) {
		if (p_select) {
			_pre_shift_selection(i);
		} else {
			deselect(i);
		}
		Point2i next_line = get_next_visible_line_index_offset_from(get_caret_line(i), get_caret_wrap_index(i), -get_visible_line_count());
		int n_line = get_caret_line(i) - next_line.x + 1;
		set_caret_line(n_line, i == 0, false, next_line.y, i);
		if (p_select) {
			_post_shift_selection(i);
		}
	}
	merge_overlapping_carets();
}
void TextEdit::_move_caret_page_down(bool p_select) {