SDK loads native TLS library even if security.enableNativeTls is false

Suggested release note:

Setting `security.enableNativeTls` to false now prevents the SDK from even attempting to load the native TLS library. (Prior to this change, the SDK would load the library and just not use it.) In addition to saving a bit of memory, this prevents the JVM from segfaulting on Alpine Linux where glibc is not available.