TruffleRuby: remove explicit `openssl@1.1` requirement on macOS

TruffleRuby build definitions used to explicitly rely on `brew --prefix openssl@1.1` on macOS and abort installation if that was not found. However, this check didn't take into account that the user might have set OPENSSL_PREFIX in their environment, or that they have another `openssl@*` version installed via Homebrew. This change removes the `use_homebrew_openssl` check and allows TruffleRuby to perform its own OpenSSL detection.

https://github.com/oracle/truffleruby/blob/vm-23.1.0/lib/truffle/truffle/openssl-prefix.rb#L14-L17