chore: update test log pattern webhook cache

[jgongd]

Description

metrics_sigma is no longer a field in single-medium-train-step.yaml. So the test need to be updated.

Test Plan

CI Passes.

Checklist

• Changes have been manually QA'd
• New features have been approved by the corresponding PM
• User-facing API changes have the "User-facing API Change" label
• Release notes have been added as a separate file under docs/release-notes/
  See Release Note for details.
• Licenses have been included for new code which was copied and/or modified from any external code

[netlify]

✅ Deploy Preview for determined-ui canceled.

Name	Link
🔨 Latest commit	66097d6
🔍 Latest deploy log	https://app.netlify.com/sites/determined-ui/deploys/66e1f9b6a14db20008581787

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 59.18%. Comparing base (de89f68) to head (66097d6).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #9922   +/-   ##
=======================================
  Coverage   59.18%   59.18%           
=======================================
  Files         751      751           
  Lines      104454   104454           
  Branches     3598     3599    +1     
=======================================
  Hits        61824    61824           
  Misses      42498    42498           
  Partials      132      132           

Flag	Coverage Δ
backend	43.80% <ø> (ø)
harness	72.75% <ø> (ø)
web	54.33% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

[azhou-determined]

nice