ci: remove deploying latest main and preview clusters

[jgongd]

Description

Remove the CI jobs that deploy/update clusters:

• latest-main cluster
• Netlify preview cluster

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

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 54.37%. Comparing base (ce78d62) to head (1869e96).

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10234      +/-   ##
==========================================
+ Coverage   54.35%   54.37%   +0.02%     
==========================================
  Files        1256     1256              
  Lines      155779   155779              
  Branches     3618     3618              
==========================================
+ Hits        84671    84704      +33     
+ Misses      70975    70942      -33     
  Partials      133      133              

Flag	Coverage Δ
backend	45.87% <ø> (+0.06%)	⬆️
harness	71.26% <ø> (ø)
web	54.45% <ø> (ø)

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

see 5 files with indirect coverage changes

[netlify]

✅ Deploy Preview for determined-ui canceled.

Name	Link
🔨 Latest commit	1869e96
🔍 Latest deploy log	https://app.netlify.com/sites/determined-ui/deploys/6751e16e17750c00082441bc