[codex] remove dead shifu.run demo mirror

[tomqin93]

What this PR does / why we need it:

Removes the legacy shifurun-ssh publish steps from the release demo artifact jobs. The public installer downloads demo packages from demo.shifu.dev, and the later shifu.dev publish step is the active destination. Keeping the old shifurun-ssh step causes release builds to fail before the artifacts can reach shifu.dev when shifu.run DNS does not resolve.

Will this PR make the community happier?

Yes. Tagged releases can publish the demo tarballs to the working shifu.dev host without being blocked by a dead legacy mirror.

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): N/A

How is this PR tested

• unit test
• e2e test
• other (please specify): parsed azure-pipelines/azure-pipelines.yml as YAML and confirmed no shifurun references remain in that pipeline file.

Special notes for your reviewer:

Build 21713 failed in CopyFilesOverSSH while resolving the old shifu.run host. The subsequent push demo file to shifu.dev step was skipped because the previous step failed.

Release note:

NONE

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 35.09%. Comparing base (c491315) to head (c2df73c).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1494   +/-   ##
=======================================
  Coverage   35.09%   35.09%           
=======================================
  Files          54       54           
  Lines        4029     4029           
=======================================
  Hits         1414     1414           
  Misses       2461     2461           
  Partials      154      154           

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