fix: set default value for users.session.duration (#9962)

[numacci21]

Fixes #9962

Checklist:

• Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this does not need to be in the release notes.
• The title of the PR states what changed and the related issues number (used for the release note).
• I've included "Closes [ISSUE #]" or "Fixes [ISSUE #]" in the description to automatically close the associated issue.
• I've updated both the CLI and UI to expose my feature, or I plan to submit a second PR with them.
• Does this PR require documentation updates?
• I've updated documentation as required by this PR.
• Optional. My organization is added to USERS.md.
• I have signed off all my commits as required by DCO
• I have written unit and/or e2e tests for my change. PRs without these are unlikely to be merged.
• My build is green (troubleshooting builds).

NOTE:

• Line 672, 1285-1287, 1320-1321, 1325 changes in settings_test.go have been automatically formatted.

[codecov]

Codecov Report

Merging #10185 (caeda75) into master (3520dfc) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master   #10185      +/-   ##
==========================================
+ Coverage   45.93%   45.94%   +0.01%     
==========================================
  Files         227      227              
  Lines       27419    27418       -1     
==========================================
+ Hits        12594    12598       +4     
+ Misses      13114    13110       -4     
+ Partials     1711     1710       -1     

Impacted Files	Coverage Δ
util/settings/settings.go	51.42% <100.00%> (+0.51%)	⬆️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[crenshaw-dev]

@y-takuya thanks so much for this!

Could you add a quick note to docs/operator-manual/upgrading/2.4-2.5.md to say something to this effect:

Invalid user.session.duration values now fall back to 24h

Before v2.5, an invalid user.session.duration value in argocd-cm would 1) log a warning and 2) result in user sessions having no duration limit.

Starting with v2.5, invalid duration values will fall back to 24 hours.

[numacci21]

@crenshaw-dev Thank you very much for your comment and for revising the PR title. I added a note with mostly what you proposed.

[crenshaw-dev]

@y-takuya the test failure is due to a problem on the master branch. I'll update your branch after the fix is merged (should be in the next ~40min).

[numacci21]

@crenshaw-dev I see. Thank you for updating my branch. The CI is still failing, but the reason was due to a network problem that failed to download the k3s binary (exit code 92). It might be a temporary issue, so I will try to re-trigger this CI again.

[crenshaw-dev]

lgtm. thanks @y-takuya!