Add error return value information for EVP_MD_get_size()

Add error return value information for EVP_MD_get_size() and
EVP_MD_CTX_get_size() to better guide their usages and avoid
the integer overflow, such as
4a508825 ("ssl_cipher_get_overhead(): Replace size_t with int and add the checks")
and ef9ac2f9 ("test/bad_dtls_test.c: Add checks for the EVP_MD_CTX_get_size()").

Signed-off-by: Jiasheng Jiang <jiashengjiangcool@outlook.com>

Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com>
Reviewed-by: Paul Dale <ppzgs1@gmail.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/25282)