Remove now unnecessary step from tests CI workflow

Author: ifox

.github/workflows/main.yml

@@ -129,10 +129,6 @@ jobs:
         run: |
           npm ci
 
-      - name: Create blocks dir
-        run: |
-          mkdir ./frontend/js/components/blocks/customs
-
       - name: Build twill.
         run: ./vendor/bin/testbench twill:build --forTesting
         env: