fix: setting spec.SyncPolicy crashes 'argocd appset get' output (#12424)

[neurodrone]

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Fixes: #12424

Previously we didn't explicitly check for the presence of spec.template.spec.SyncPolicy before accessing its .Automated struct variable which led to a nil pointer dereference issue.

[codecov]

Codecov Report

Base: 47.71% // Head: 47.77% // Increases project coverage by +0.05% 🎉

Coverage data is based on head (1b13627) compared to base (fbb0b99).
Patch coverage: 80.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #12425      +/-   ##
==========================================
+ Coverage   47.71%   47.77%   +0.05%     
==========================================
  Files         246      246              
  Lines       41908    41911       +3     
==========================================
+ Hits        19996    20021      +25     
+ Misses      19914    19891      -23     
- Partials     1998     1999       +1     

Impacted Files	Coverage Δ
cmd/argocd/commands/applicationset.go	17.05% <80.00%> (+8.27%)	⬆️
util/settings/settings.go	49.36% <0.00%> (ø)

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[blakepettersson]

This makes sense to me, is there any chance you could add unit tests for this fix (I'm aware that most of the CLI commands are lacking unit tests, but the boy scout rule and all of that? 😄)?

[neurodrone]

Thanks @blakepettersson for eyeing this! I updated the code with a test to test all permutations of syncPolicies just in case. :) Please let me know if anything else needs to be changed.

[blakepettersson]

LGTM 😄

[crenshaw-dev]

Cherry-picked onto release-2.5 for 2.5.12, and release-2.6 for 2.6.3.