Remove ASN1_STRING_data for LibreSSL 4.3.0

[botovq]

This API has been deprecated since forever and will be removed.

I'd actually prefer doing this for rust-openssl, so we can remove this API when we drop support for OpenSSL 1.0.2:

-    #[cfg(any(all(ossl102, not(ossl110)), libressl))]
+    #[cfg(all(ossl102, not(ossl110)))]

But of course doing this would be a semver breaking change.

Really the only reason for ASN1_STRING_data to be bound at all is the lack of the const-correct ASN1_STRING_get0_data in very old Open/LibreSSLs