Change icon from cross to [i] for root user check

[yubiuser]

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What does this PR aim to accomplish?:
Change the icon from cross to [i] when performing root user check. As discussed here

[dschaper]

I think this needs to stay a cross. You can not run the script as non-sudo so it is indeed an error.

[yubiuser]

At this points it just informs the user that it needs root privileges, the check for sudo comes a few lines later and will fail if sudo does not exist.

[dschaper]

Yes, it's still an error.

[DL6ER]

I agree with @yubiuser about this change. If the user runs this as non-root (the typical scenario), it will just re-curl and sudo bash the installer. If this does not work (because the user doesn't know their password, etc.), sudo will give them a much more useful output. If sudo is not available, the user will be informed about this fact (and a cross is shown).

[PromoFaux]

See my comments here:
https://discourse.pi-hole.net/t/pi-hole-5-probleme-in-kombination-mit-fritzbox-7490/32665/143?u=promofaux

[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-core-web-v5-2-and-ftl-v5-3-released/40909/1

[pralor-bot]

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

https://discourse.pi-hole.net/t/error-non-root-privileges-why-does-this-always-happen/42091/11