Cause a connection abort when HTTP/2-only frame and settings types are received in...

Cause a connection abort when HTTP/2-only frame and settings types are received in HTTP/3. (Progress toward HTTP/3 draft 31 compat) (#43287)

Send h3-29 through h3-31 for ALPN as we are compatible with all of them.
Move some of the loopback test code into the stream class rather than connection class.
Add a basic test for SETTINGS frame receipt.
Fix some tests that were explicitly using Http3LoopbackServer and did not see the new "Mock" QUIC setting introduced in https://github.com/dotnet/runtime/pull/43076