fix: Provide better error message when application source is missing some settings

[cleverhu]

Closes: #10684
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).

[codecov]

Codecov Report

Base: 45.75% // Head: 45.75% // No change to project coverage 👍

Coverage data is based on head (ca3e776) compared to base (02bf903).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #10694   +/-   ##
=======================================
  Coverage   45.75%   45.75%           
=======================================
  Files         236      236           
  Lines       28527    28527           
=======================================
  Hits        13053    13053           
  Misses      13669    13669           
  Partials     1805     1805           

Impacted Files	Coverage Δ
util/argo/argo.go	64.43% <100.00%> (ø)
util/settings/settings.go	51.36% <0.00%> (ø)

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[jannfis]

LGTM! Thanks @cleverhu !