Fix getting 'privacylevel'

[yubiuser]

What does this PR aim to accomplish?:

Better re-implementation of #5177.
Using the sed | grep | awk directly within the installation script should prevent update failures while utils.sh is still not updated.

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[PromoFaux]

pi@raspberrypi:~ $ sed -e '/^[[:blank:]]*#/d' /etc/pihole/pihole-FTL.conf | grep "PRIVACYLEVEL" | awk -F "=" 'NR==1{printf$2}'
0

[pralor-bot]

This pull request has been mentioned on Pi-hole Userspace. There might be relevant details there:

https://discourse.pi-hole.net/t/pi-hole-ftl-v5-22-web-v5-19-and-core-v5-16-1-released/61999/1