[DEVOPS-673] build-installer-unix.sh: don't npm install twice
[DEVOPS-673] build-installer-unix.sh: don't npm install twice

input-output-hk/daedalus,input-output-hk/daedalus,input-output-hk/daedalus,input-output-hk/daedalus,input-output-hk/daedalus,input-output-hk/daedalus