What would you like to be added:

For TLSRoutes:

1. Mark hostnames as non-optional.
2. Set min hostnames length to 1.

Why this is needed:

1. SNI hostnames is the only match available for TLSRoutes. If SNI hostname matching is not needed, TCPRoute should be used instead.
2. The TLSRoute spec requires at lear 1 hostname to be specified.
   Note: We'll re-evaluate the "non-optional" restriction if future GEPs for TLSRoutes allow routing based on other TLS handshake attributes like ALPN.