Minor bug in build_support/packages.sh

[yxd0379]

In the file build_support/packages.sh, there is an incorrect line (brew ls --versions llvm | grep 14) || brew install llvm@14 in the install_mac function.

The original command always prints nothing, so it will always directly execute the install command, which is not the expected behavior.

It should be modified to brew ls --versions llvm@14 || brew install llvm@14 to correctly check if llvm@14 is installed.