Avoid undefined behavior of provided macs on EVP_MAC reinitialization

Avoid undefined behavior of provided macs on EVP_MAC reinitialization

When the context is reinitialized, i.e. the same key should be used
we must properly reinitialize the underlying implementation.

However in POLY1305 case it does not make sense as this special MAC
should not reuse keys. We fail with this provided implementation
when reinitialization happens.

Fixes #17811

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18100)