ci(release): create prerelease releases

[lixd]

/kind cleanup

What this PR does / why we need it:

Set prerelease: true for the Console GitHub release workflow so tag-triggered releases remain prereleases until the release is manually promoted.

Which issue(s) this PR fixes:

Fixes #

Special notes for reviewers:

The current release workflow only changes the GitHub Release status; OSS upload paths and release assets are unchanged.

Does this PR introduced a user-facing change?

None

None

Additional documentation, usage docs, etc.:

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 47.30%. Comparing base (c8ec5fe) to head (5ce4bc6).
⚠️ Report is 6 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #432   +/-   ##
=======================================
  Coverage   47.30%   47.30%           
=======================================
  Files           7        7           
  Lines         613      613           
  Branches      176      176           
=======================================
  Hits          290      290           
  Misses        250      250           
  Partials       73       73           

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[lixd]

/lgtm