Allow TLS 1.2 servers to report client versions from the supported ve…

…rsions extension

Squashed commit of the following:

commit 2b3c9b2
Author: Sam Clark <3758302+goatgoose@users.noreply.github.com>
Date:   Tue Oct 17 16:01:14 2023 -0400

    fixes

commit 3e27ec8
Author: Sam Clark <3758302+goatgoose@users.noreply.github.com>
Date:   Tue Oct 17 15:31:45 2023 -0400

    update integ test to expect TLS 1.3

commit b66a361
Author: Sam Clark <3758302+goatgoose@users.noreply.github.com>
Date:   Tue Oct 17 11:44:41 2023 -0400

    fixes

commit c3b120b
Author: Sam Clark <3758302+goatgoose@users.noreply.github.com>
Date:   Tue Oct 17 11:38:17 2023 -0400

    TLS 1.2 fallback tests

commit 4245e3e
Author: Sam Clark <3758302+goatgoose@users.noreply.github.com>
Date:   Mon Oct 16 16:54:54 2023 -0400

    add test for client getters

commit 7e8e734
Author: Sam Clark <3758302+goatgoose@users.noreply.github.com>
Date:   Mon Oct 16 14:35:05 2023 -0400

    add test for server getters with no supported versions extension

commit 9f63693
Author: Sam Clark <3758302+goatgoose@users.noreply.github.com>
Date:   Mon Oct 16 14:09:27 2023 -0400

    test for protocol getters on server with a received supported versions extension

commit 08d3d78
Author: Sam Clark <3758302+goatgoose@users.noreply.github.com>
Date:   Mon Oct 16 10:29:51 2023 -0400

    add supported versions RFC exception for legacy client hello version

commit 4026318
Author: Sam Clark <3758302+goatgoose@users.noreply.github.com>
Date:   Fri Oct 13 11:37:45 2023 -0400

    parse supported versions extension in getter

commit 4ee56eb
Author: Sam Clark <3758302+goatgoose@users.noreply.github.com>
Date:   Fri Oct 13 10:17:13 2023 -0400

    refactor supported versions process

tests/integrationv2/test_version_negotiation.py

@@ -77,12 +77,12 @@ def test_s2nc_tls13_negotiates_tls12(managed_process, cipher, curve, certificate
 
     for results in server.get_results():
         results.assert_success()
+        # This check only cares about S2N. Trying to maintain expected output of other providers doesn't add benefit to
+        # whether the S2N client was able to negotiate a lower TLS version.
         if provider is S2N:
-            # The server is only TLS12, so it reads the version from the CLIENT_HELLO, which is never above TLS12
-            # This check only cares about S2N. Trying to maintain expected output of other providers doesn't
-            # add benefit to whether the S2N client was able to negotiate a lower TLS version.
+            # The client sends a TLS 1.3 client hello so a client protocol version of TLS 1.3 should always be expected.
             assert to_bytes("Client protocol version: {}".format(
-                actual_version)) in results.stdout
+                Protocols.TLS13.value)) in results.stdout
             assert to_bytes("Actual protocol version: {}".format(
                 actual_version)) in results.stdout