Various fixes

[qstokkink]

Fixes #8778
Fixes #8728
Fixes #8770

This PR:

• Fixes startup error(s) when Sesssion.rust_endpoint is None.
• Fixes Mac validation tests taking eons (i.e., 7 minutes) in LAN address detection overhead.
• Fixes an error where torrents with file flags would have no (visible) files.
• Fixes torrent_finished_alert not propagating due to it needing handle.info_hash() instead of params.info_hash.
• Fixes torrents downloading without selected files when Always ask download settings was disabled. Changed to all files by default.