Revert back to bare metal runners for weights generation

Author: Oleg Plakida

scripts/ci/gitlab/pipeline/weights.yml

@@ -21,7 +21,7 @@ update_polkadot_weights:           &update-weights
     - git diff -P > ${RUNTIME}_weights_${CI_COMMIT_SHORT_SHA}.patch
   # uses the "shell" executors
   tags:
-    - weights-vm
+    - weights
 
 update_kusama_weights:
   <<:                              *update-weights