test: run DNS validation against more than one query

[jackfrancis]

Reason for Change:

We shouldn't test just one FQDN for DNS resolution during E2E

Issue Fixed:

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• tested upgrade from previous version

Notes:

[codecov]

Codecov Report

Merging #1983 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1983      +/-   ##
==========================================
- Coverage   76.71%   76.71%   -0.01%     
==========================================
  Files         135      135              
  Lines       20573    20557      -16     
==========================================
- Hits        15783    15770      -13     
+ Misses       3873     3871       -2     
+ Partials      917      916       -1

[mboersma]

/lgtm

[acs-bot]

[APPROVALNOTIFIER] This PR is APPROVED

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