RFC 6763/6: ServiceInfo _is_complete() returns True even if no TXT record has been received #1815

According to RFC 6763/6, every DNS-SD service must have a TXT record along with the SRV:

https://datatracker.ietf.org/doc/html/rfc6763#section-6

Every DNS-SD service MUST have a TXT record in addition to its SRV
record, with the same name, even if the service has no additional
data to store and the TXT record contains no more than a single zero
byte.

In ServiceInfo, a service is considered "complete" if: bool(self.text is not None and (self._ipv4_addresses or self._ipv6_addresses)). It seems like this was initially implemented to ensure a TXT record was received, however as far as I can tell self.text is never None. In the constructor, it is defaulted to an empty string so if the service has addresses but no TXT record, the record is still considered "complete".

In my use case, this has caused an issue where zeroconf says the service is fully resolved, but is missing the TXT record.

I can submit a PR to fix this issue, but wanted to confirm that this is a real issue and not expected.

Thanks.