Run macOS CI on both Intel and Apple Silicon

[DilumAluthge]

This PR does the following:

1. Run macOS CI on both Intel and Apple Silicon
2. Fix a CI config bug regarding 32-bit vs 64-bit Julia

#973 was merged into this PR.

---

For reference, in GitHub Actions:

• runs-on: macos-13 = Intel.
• runs-on: macos-14 = Apple Silicon.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.56%. Comparing base (b4201d8) to head (7988658).
Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #970   +/-   ##
=======================================
  Coverage   84.56%   84.56%           
=======================================
  Files           3        3           
  Lines         823      823           
=======================================
  Hits          696      696           
  Misses        127      127           

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[DilumAluthge]

CI is all green.