Do not consider false positives as invalid domains

[rdwebdesign]

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What does this PR aim to accomplish?:

The new gravity_parseList() function was created to replace part of the gravity code, but we found a small difference in the way "false positives" are counted.

This PR changes this to achieve the same output shown by the original gravity.

How does this PR accomplish the above?:

Excluding false positives from the invalid_domains count.

Link documentation PRs if any are needed to support this PR:

none

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[yubiuser]

I think the logic is now correct and also the gravity output looks good. I suggest two small comment modifications.

[DL6ER]

👍