decapsulate method
Decapsulates the last protocol/value pair from this multiaddr
Implementation
MultiAddr? decapsulate(String protocol) {
final index = _components.lastIndexWhere((c) => c.$1.name == protocol);
if (index == -1) return null;
final newComponents = _components.take(index);
final newAddr = newComponents.map((c) => '/${c.$1.name}/${c.$2}').join();
return MultiAddr(newAddr);
}