fix(iroh-docs): do not dial invalid peers

[dignifiedquire]

Description

Breaking Changes

Notes & open questions

Change checklist

• Self-review.
• Documentation updates following the style guide, if relevant.
• Tests if relevant.
• All breaking changes documented.

[dignifiedquire]

okay, sync tests are broken, this seems to trigger either another bug, or this fix is incorrect

[Frando]

The fix was incorrect, pushed two commits:

• we need to join gossip also if no peers are set.
• we may not skip node addrs that have empty address info.

For the last one - We maybe should change iroh_net so that Endpoint::add_node_addr does not error if called with a NodeAddr with emtpy AddrInfo (only NodeId set) because it seems cumbersome to check at the user level if the addr contains addr info or not, usually you get these from a ticket or some protocol and just want to add them in case they contain useful info and don't care if not because node discovery is enabled. But that can be a followup.