fix: create PR releases even when test suite fails (#12202)

This PR fixes an issue where PR releases were not created when the test
suite failed, even though the build artifacts were available. The
workflow now runs whenever a PR's CI completes, regardless of
success/failure, and relies on the artifact verification step to ensure
the necessary build artifacts exist before proceeding.

This allows developers to get PR toolchains and test against Mathlib
even when the Lean test suite has failures, as long as the build jobs
succeeded.

🤖 Prepared with Claude Code

Co-authored-by: Claude <noreply@anthropic.com>

.github/workflows/pr-release.yml

@@ -20,7 +20,9 @@ on:
 jobs:
   on-success:
     runs-on: ubuntu-latest
-    if: github.event.workflow_run.conclusion == 'success' && github.event.workflow_run.event == 'pull_request' && github.repository == 'leanprover/lean4'
+    # Run even if CI fails, as long as build artifacts are available
+    # The "Verify release artifacts exist" step will fail if necessary artifacts are missing
+    if: github.event.workflow_run.event == 'pull_request' && github.repository == 'leanprover/lean4'
     steps:
       - name: Retrieve information about the original workflow
         uses: potiuk/get-workflow-origin@v1_1 # https://github.com/marketplace/actions/get-workflow-origin