Do not accept comma to separate regex

[DL6ER]

What does this implement/fix?

Domains/Regex must be either space or newline separated when adding multiple at once. It is not possible to use comma as this has a special meaning in the regex world

Can be tested by adding

google{1,2}

Before:

Now:

It is advisable to use FTL from PR pi-hole/FTL#1759 to prevent FTL from crashing during the review test.

Fixes #2834

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Related issue or feature (if applicable): N/A

Pull request in docs with documentation (if applicable): N/A

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[yubiuser]

Should we also remove the ability to split adlists, groups,clients by comma just to make it more consistent (and to match the hint which only says "space-seperated")?

[DL6ER]

I was thinking about this but thought that it may actually be good to be somewhat more generous concerning separators where they don't cause trouble. My feeling is that users will simply try this without actually reading anything