fix: handle empty array as nil when filling record defaults

[aboudreault]

To avoid panic errors, in case of a wrong [] being set in the config for a record field, let's treat it as a nil and create the proper object map.

Can be reproduced with a deck sync:

_format_version: "3.0"
plugins:
- config:
    storage_config:
      redis: []
  enabled: true
  name: acme

[codecov-commenter]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.06 🎉

Comparison is base (a49e916) 52.77% compared to head (c7b2f8e) 52.84%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #345      +/-   ##
==========================================
+ Coverage   52.77%   52.84%   +0.06%     
==========================================
  Files          69       69              
  Lines        5095     5102       +7     
==========================================
+ Hits         2689     2696       +7     
  Misses       1832     1832              
  Partials      574      574              

Flag	Coverage Δ
2.1.4	17.71% <100.00%> (-18.58%)	⬇️
2.2.1.3	?
2.2.2	17.71% <100.00%> (-18.58%)	⬇️
2.3.3	17.77% <100.00%> (-18.58%)	⬇️
2.3.3.4	?
2.4.1	36.04% <100.00%> (-0.39%)	⬇️
2.4.1.3	47.58% <100.00%> (+0.07%)	⬆️
2.5.1.2	47.58% <100.00%> (+0.07%)	⬆️
2.5.2	?
2.6.1	36.51% <100.00%> (+0.08%)	⬆️
2.6.1.0	?
2.7.2	17.85% <100.00%> (-18.58%)	⬇️
2.7.2.0	?
2.8.3	17.85% <100.00%> (-18.58%)	⬇️
2.8.4.0	49.11% <100.00%> (+0.06%)	⬆️
3.0.2	17.85% <100.00%> (-18.03%)	⬇️
3.0.2.0	49.56% <100.00%> (+0.06%)	⬆️
3.1.1	17.85% <100.00%> (-19.52%)	⬇️
3.1.1.3	51.05% <100.00%> (+0.06%)	⬆️
3.2.2	17.91% <100.00%> (-19.52%)	⬇️
3.2.2.1	?
community	38.06% <100.00%> (+0.08%)	⬆️
enterprise	51.60% <100.00%> (+0.06%)	⬆️
enterprise-nightly	?
integration	52.84% <100.00%> (+0.06%)	⬆️
nightly	37.51% <100.00%> (+0.08%)	⬆️

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

Impacted Files	Coverage Δ
kong/utils.go	88.33% <100.00%> (+0.24%)	⬆️

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[pmalek]

3 things I'd like to raise here:

• Add a reference of koko case in the code comment so that we know which issue this is related to
• This definitely deserves a changelog entry
• A test case should be added. There already exists Test_fillConfigRecord so it should be as easy as adding another table driver test case there

[pmalek]

Small nits, I applied those right away to speed up the delivery of this patch.

Thanks for adding changelog and tests! 🙇