fix(playwright): remove Google Sheets dependency from dataset tests (#39143)

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/bashlib.sh

@@ -127,6 +127,20 @@ playwright_testdata() {
   superset load_test_users
   superset load_examples
   superset init
+  # Enable DML on the examples database so Playwright tests can create/drop
+  # temporary tables via SQL Lab without depending on external data sources.
+  superset shell <<'PYEOF'
+import sys
+from superset.extensions import db
+from superset.models.core import Database
+examples_db = db.session.query(Database).filter_by(database_name='examples').first()
+if not examples_db:
+    sys.exit('ERROR: examples database not found. load_examples may have failed.')
+
+examples_db.allow_dml = True
+db.session.commit()
+print('Enabled allow_dml on examples database')
+PYEOF
   say "::endgroup::"
 }