Update osx installers and urlchecker environment

[jsiirola]

Fixes # .

Summary/Motivation:

This resolves a pair of longstanding irritations:

• the OSX environment setup logged errors (looking for packages that were not installed) that were picked up by GHA and included in the job summary. This PR suppresses those messages
• the urlchecker was having intermittent errors (particularly with servers like egon.cheme.cmu.edu). @jdawber223 suggested that it might be an intermittent issue with Google DNS lookups for CMU machines. This PR sets the DNS servers to CloudFare before running the urlchecker (which might resolve the problem)

Changes proposed in this PR:

• (see above)

Legal Acknowledgement

By contributing to this software project, I have read the contribution guide and agree to the following terms and conditions for my contribution:

1. I agree my contributions are submitted under the BSD license.
2. I represent I am authorized to make the contributions and grant the license. If my employer has rights to intellectual property that includes these contributions, I represent that I have received permission to make contributions and grant the required license on behalf of that employer.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.94%. Comparing base (43a6446) to head (ed5afee).
⚠️ Report is 5 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3914   +/-   ##
=======================================
  Coverage   89.94%   89.94%           
=======================================
  Files         902      902           
  Lines      106457   106457           
=======================================
+ Hits        95748    95751    +3     
+ Misses      10709    10706    -3     

Flag	Coverage Δ
builders	29.18% <ø> (+<0.01%)	⬆️
default	86.24% <ø> (?)
expensive	35.64% <ø> (?)
linux	87.39% <ø> (-2.04%)	⬇️
linux_other	87.39% <ø> (ø)
oldsolvers	28.11% <ø> (+<0.01%)	⬆️
osx	82.72% <ø> (ø)
win	85.82% <ø> (ø)
win_other	85.82% <ø> (ø)

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