Attenuate non-domain warning

[yubiuser]

What does this PR aim to accomplish?:

Front-end change for pi-hole/pi-hole#5128

Renames "invalid domains" to "non-domains" and removed the red & bold text style.

---

By submitting this pull request, I confirm the following:

1. I have read and understood the contributors guide, as well as this entire template. I understand which branch to base my commits and Pull Requests against.
2. I have commented my proposed changes within the code and I have tested my changes.
3. I am willing to help maintain this change if there are issues with it later.
4. It is compatible with the EUPL 1.2 license
5. I have squashed any insignificant commits. (git rebase)
6. I have checked that another pull request for this purpose does not exist.
7. I have considered, and confirmed that this submission will be valuable to others.
8. I accept that this submission may not be used, and the pull request closed at the will of the maintainer.
9. I give this submission freely, and claim no ownership to its content.

---

• I have read the above and my PR is ready for review. Check this box to confirm

[yubiuser]

Removing the warning triangle could also be discussed.

[PromoFaux]

Removing the warning triangle could also be discussed.

I think we should remove it for sure It does make the problem seem larger than it is - in that, it is not a problem at all for Pi-hole.

Maybe a tooltip/hint on the non-domains line that briefly explains what we mean by non-domains. Not sure

[yubiuser]

Triangle removed as well.

[PromoFaux]

The numbers don't match up, but I suspect that's something in the core PR...

[PromoFaux]

It was on the other PR

[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-web-v5-18-2-and-core-v5-15-1-released/60695/1