fix: Updated default config to accept undefined as default value

[svetlanabrennan]

Description

Our current configuration doesn't allow an undefined value for a 3 layers deep/nested config item. This PR allows that now.

How to Test

Run unit tests

Related Issues

Fixes #2871

[bizob2828]

LGTM

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.60%. Comparing base (cc65763) to head (14672bd).
Report is 15 commits behind head on main.

❗ There is a different number of reports uploaded between BASE (cc65763) and HEAD (14672bd). Click for more details.

HEAD has 8 uploads less than BASE

Flag	BASE (cc65763)	HEAD (14672bd)
unit-tests-18.x	1	0
unit-tests-22.x	1	0
unit-tests-20.x	1	0
integration-tests-cjs-18.x	1	0
integration-tests-cjs-20.x	1	0
integration-tests-esm-18.x	1	0
versioned-tests-18.x	1	0
integration-tests-esm-20.x	1	0

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2917      +/-   ##
==========================================
- Coverage   97.39%   88.60%   -8.80%     
==========================================
  Files         310      312       +2     
  Lines       47512    47635     +123     
==========================================
- Hits        46276    42208    -4068     
- Misses       1236     5427    +4191     

Flag	Coverage Δ
integration-tests-cjs-18.x	?
integration-tests-cjs-20.x	?
integration-tests-cjs-22.x	72.70% <100.00%> (-0.37%)	⬇️
integration-tests-esm-18.x	?
integration-tests-esm-20.x	?
integration-tests-esm-22.x	49.67% <100.00%> (-0.17%)	⬇️
unit-tests-18.x	?
unit-tests-20.x	?
unit-tests-22.x	?
versioned-tests-18.x	?
versioned-tests-20.x	79.23% <100.00%> (-0.23%)	⬇️
versioned-tests-22.x	79.24% <100.00%> (-0.23%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[jsumners-nr]

🎉