FIX(client): Use IPv4 HostAddress representation where applicable

In 6c56568 the HostAddress was refactored. A check for isV6 when
creating a QHostAddress was removed. However, the QHostAddress
determines the (IPv4 vs IPv6) distinction at construction time.
This resulted in some regressions both visually and functional.

This commit reintroduces the distinction.

Fixes mumble-voip#6349

src/HostAddress.cpp

@@ -137,7 +137,11 @@ bool HostAddress::isValid() const {
 }
 
 QHostAddress HostAddress::toAddress() const {
-	return QHostAddress(m_byteRepresentation.data());
+	QHostAddress address = QHostAddress(m_byteRepresentation.data());
+	if (!isV6()) {
+		address.setAddress(address.toIPv4Address());
+	}
+	return address;
 }
 
 QByteArray HostAddress::toByteArray() const {