### 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
StringBuilder ret_text;
	const int text_size = text.size();
	for (int i = 0; i < text_size; i++) {
		ret_text += text[i];
		if (i != text_size - 1) {
			ret_text += "\n";
		}
	}
	return ret_text.as_string();
}
int TextEdit::get_line_count() const {
	return text.size();
}
void TextEdit::set_placeholder(const String &p_text) {