fix(metricprovider): implement Terminate for Kayenta provider. Fixes #4815

[Goutham-Annem]

Fixes #4815

Problem

The Kayenta metric provider is asynchronous — Run() POSTs a canary analysis job and returns AnalysisPhaseRunning, then Resume() polls until the job completes. When an AnalysisRun is terminated while a Kayenta measurement is in-flight, the controller calls Terminate() on the provider.

Previously, Terminate() only logged a warning and returned the measurement unchanged (still with AnalysisPhaseRunning). Because the analysis framework only considers the AnalysisRun terminated once all measurements reach a completed phase, the stuck AnalysisPhaseRunning measurement caused a resource leak — the AnalysisRun could never fully terminate.

Fix

Set FinishedAt and transition the measurement phase to AnalysisPhaseSuccessful so the normal termination path in analysis.go can proceed. Since Kayenta does not expose a job cancellation API the in-flight analysis job is left to expire naturally on Kayenta's side; only the controller-side measurement state needs to be resolved.

Also corrects the misleading doc comment on Resume(), which incorrectly stated the method would never be called — in fact Resume() is the polling path for every in-flight Kayenta measurement.

Testing

• Updated the existing TestRunSuccessfully test to assert that Terminate sets AnalysisPhaseSuccessful and a non-nil FinishedAt.
• Added a dedicated TestTerminate test covering the standalone Terminate path.

$ go test ./metricproviders/kayenta/...
ok      github.com/argoproj/argo-rollouts/metricproviders/kayenta      0.532s

Checklist

• Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this is a chore.
• The title of the PR is (a) conventional with a list of types and scopes found here, (b) states what changed, and (c) suffixes the related issues number.
• I've signed my commits with DCO
• I have written unit and/or e2e tests for my change.
• I have used LLM/AI/Agent tools for this PR but I am responsible for all code of this PR
• I understand what the code does and WHY/HOW it works in several scenarios
• I know if my code is just adding new functionality or changing old functionality for existing users

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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[github-actions]

Published E2E Test Results

  4 files    4 suites   3h 45m 4s ⏱️
122 tests 115 ✅  7 💤 0 ❌
488 runs  460 ✅ 28 💤 0 ❌

Results for commit e2fc199.

[github-actions]

Published Unit Test Results

2 517 tests   2 517 ✅  3m 23s ⏱️
  130 suites      0 💤
    1 files        0 ❌

Results for commit e2fc199.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.97%. Comparing base (d1c2967) to head (e2fc199).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4825      +/-   ##
==========================================
- Coverage   85.09%   84.97%   -0.12%     
==========================================
  Files         166      166              
  Lines       19136    19139       +3     
==========================================
- Hits        16283    16264      -19     
- Misses       2005     2016      +11     
- Partials      848      859      +11     

Flag	Coverage Δ
e2e	52.71% <0.00%> (-0.26%)	⬇️
unit-tests	81.39% <100.00%> (+<0.01%)	⬆️

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