Revert npm publish workflow runner to ubuntu-latest

Blacksmith runners are classified as self-hosted, which causes
npm publish --provenance to fail with E422 because npm's Sigstore
provenance verification requires GitHub-hosted runners.

Co-authored-by: Andrew Gable <AndrewGable@users.noreply.github.com>

Author: MelvinBot

.github/workflows/npmPublish.yml

@@ -21,7 +21,7 @@ on:
 
 jobs:
   publish:
-    runs-on: blacksmith-2vcpu-ubuntu-2404
+    runs-on: ubuntu-latest
     permissions:
       contents: read
       id-token: write # Required for OIDC: https://docs.npmjs.com/trusted-publishers