Don't print double newlines after invalid domains

[yubiuser]

Don't print double newlines after invalid domains.

  [i] Target: https://v.firebog.net/hosts/Easyprivacy.txt
  [✓] Status: Retrieval successful
  [✓] Parsed 32268 exact domains and 0 ABP-style domains (blocking, ignored 5 non-domain entries)
      Sample of non-domain entries:
        - emam
        - smcom
        - smetriccom
        - smetrics.previcox.d
        - welcome..org


  [i] Target: https://v.firebog.net/hosts/Prigent-Ads.txt
  [✓] Status: Retrieval successful
  [✓] Parsed 3700 exact domains and 0 ABP-style domains (blocking, ignored 0 non-domain entries)

  [i] Target: https://raw.githubusercontent.com/FadeMind/hosts.extras/master/add.2o7Net/hosts
  [✓] Status: Retrieval successful
  [✓] Parsed 2030 exact domains and 0 ABP-style domains (blocking, ignored 0 non-domain entries)

  [i] Target: https://raw.githubusercontent.com/crazy-max/WindowsSpyBlocker/master/data/hosts/spy.txt
  [✓] Status: Retrieval successful
  [✓] Parsed 347 exact domains and 0 ABP-style domains (blocking, ignored 0 non-domain entries)

  [i] Target: file:///etc/pihole/test_list.txt
  [✓] Status: Retrieval successful
  [✓] Parsed 0 exact domains and 1 ABP-style domains (blocking, ignored 1 non-domain entries)
      Sample of non-domain entries:
        - com


  [✓] Building tree
  [i] Number of gravity domains: 354963 (352248 unique domains)

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