Always run the "Build extensions" step

This ensures we will always have the artifacts to easily test PRs
using the "load unpacked" method, or for manual publishing.

.github/workflows/build.yml

@@ -87,11 +87,10 @@ jobs:
         run: EMBER_ENV=test yarn ember test --path dist --filter="Ember Debug"
 
   build:
-    name: Build for publishing
+    name: Build extensions
     needs:
       - test
       - ember-try
-    if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags/v')
     runs-on: ubuntu-latest
     env:
       CI: 'true'