chore: Added unit tests and fix e2e tests for application sync decoupling feature

[anandf]

Improvements done to the Application sync decoupling feature done as part of PR #17403

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).
• The title of the PR conforms to the Toolchain Guide
• 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.
• 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).
• My new feature complies with the feature status guidelines.
• I have added a brief description of why this PR is necessary and/or what this PR solves.
• Optional. My organization is added to USERS.md.
• Optional. For bug fixes, I've indicated what older releases this fix should be cherry-picked into (this may or may not happen depending on risk/complexity).

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[codecov]

Codecov Report

Attention: Patch coverage is 69.23077% with 4 lines in your changes missing coverage. Please review.

Project coverage is 55.87%. Comparing base (b824956) to head (3b0a3b7).

Files with missing lines	Patch %	Lines
controller/sync.go	70.00%	2 Missing and 1 partial ⚠️
util/settings/settings.go	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #19966      +/-   ##
==========================================
+ Coverage   55.85%   55.87%   +0.02%     
==========================================
  Files         321      321              
  Lines       44490    44496       +6     
==========================================
+ Hits        24849    24863      +14     
+ Misses      17077    17069       -8     
  Partials     2564     2564              

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