auth 4.9: do not disable ns records at apex in consumer zones

[Habbie]

Short description

backport of #13841

Checklist

I have:

• read the CONTRIBUTING.md document
• compiled this code
• tested this code
• included documentation (including possible behaviour changes)
• documented the code
• added or modified regression test(s)
• added or modified unit test(s)
• checked that this code was merged to master

[coveralls]

Pull Request Test Coverage Report for Build 8280019711

Details

• 3 of 3 (100.0%) changed or added relevant lines in 1 file are covered.
• 11 unchanged lines in 6 files lost coverage.
• Overall coverage increased (+0.05%) to 63.043%

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Files with Coverage Reduction	New Missed Lines	%
pdns/packethandler.cc	1	72.56%
pdns/iputils.hh	1	68.24%
pdns/misc.cc	1	48.78%
pdns/signingpipe.cc	2	86.02%
pdns/ws-auth.cc	2	80.8%
pdns/iputils.cc	4	32.87%

Totals
Change from base Build 8278809341:	0.05%
Covered Lines:	41622
Relevant Lines:	59289

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💛 - Coveralls