Stop upgrading client to intro connections to ntor

Split off from #19163 (moved), placed in the same milestone.

Clients inadvertently upgrade to ntor when the hidden service descriptor does not have a TAP onion key. This is a client discriminator that can be used by hidden services to discover which consensus a client has.

This bug was inadvertently introduced along with ntor in 0.2.4.8-alpha.

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information