Fix supported_groups handing in TLSv1.2

Fix supported_groups handing in TLSv1.2

In TLSv1.2 we should not attempt to use a supported_group value that is
intended for use with TLSv1.3 - even if both the server and the client
support it, e.g. the ffdhe groups are supported by OpenSSL for TLSv1.3 but
not for TLSv1.2.

Fixes #21081

Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/21274)