Drop duplicate if: key on publish-release job

Merge of origin/main into darwin-std-pkg landed two copies of the
`if: github.ref == 'refs/heads/main'` guard on the publish-release job:
one above `needs:` and one below it. YAML mappings can't have duplicate
keys, so GitHub Actions rejected the workflow at parse time:

  Invalid workflow file: .github/workflows/build-python-version.yml#L1
  (Line: 204, Col: 5): 'if' is already defined

Both copies were the same condition (added independently on each side of
the merge), so removing the second one is purely syntactic — no behavior
change.

Author: FeodorFitsner

.github/workflows/build-python-version.yml

@@ -201,7 +201,6 @@ jobs:
       - build-android
       - build-linux
       - build-windows
-    if: github.ref == 'refs/heads/main'
     permissions:
       contents: write
     steps: