[7.x] Ensure generated testbench.yaml is configured with App\\ and Database\\ instead of Workbench\App\\ and Workbench\Database\\ based on configured namespaces

[7.x] Ensure generated testbench.yaml is configured with App\\ and Database\\ instead of Workbench\App\\ and Workbench\Database\\ based on configured namespaces #1112