fix: declare -lcrypto in the FIPS OpenSSL cgo package (#50375)

The boringcrypto-only cgo package pkg/util/fips/openssl_enabled.go calls
libcrypto symbols (OSSL_LIB_CTX_load_config,
EVP_default_properties_is_fips_enabled,
RAND_bytes) but declared no link dependency, so FIPS builds failed at
the Go
external-link step with "libcrypto.so.3: DSO missing from command line".
The link
only used to succeed when a transitive library re-exported those
symbols.

Declare the dependency in the package that needs it via `#cgo LDFLAGS:
-lcrypto`
rather than adding -lcrypto to CGO_LDFLAGS in the Makefile/environment.
A
package-scoped directive leaves the recorded CGO_LDFLAGS build setting
empty, so it
does not change the package hash of other cgo packages and does not
require every
Go plugin to be rebuilt with a matching flag to keep plugin.Open
working.

Verified on a real FIPS build: bin/milvus links libcrypto.so.3 directly,
while the
hook/autoindex/cipher plugins keep empty CGO_LDFLAGS, carry no libcrypto
dependency,
and pass the plugin.Open package-hash check.

issue: #50374

Signed-off-by: yangxuan <xuan.yang@zilliz.com>

pkg/util/fips/openssl_enabled.go

@@ -19,6 +19,7 @@
 package fips
 
 /*
+#cgo LDFLAGS: -lcrypto
 #include <openssl/conf.h>
 #include <openssl/evp.h>
 #include <openssl/provider.h>