Add back check for the DH public key size

Add back check for the DH public key size

This is needed for TLS-1.3.

Also add check for uncompressed point format for ECDHE as
the other formats are not allowed by RFC 8446.

Fixes #17667

Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/17678)