Add missing container-parameters to Data before BeforeDiscovery

[fflaten]

PR Summary

Add default values for unused script parameters to container's Data before executing BeforeDiscovery. Avoids changes to the variables in BeforeDiscover from being captured and sent to Run-phase.

Known limitation: Changing the variable outside BeforeDiscovery/Describe/Context would still modify it in Data. Can't fix as we don't have a hook to execute code before it. Root-level code is also discouraged in Pester v5.

Fix #2359

PR Checklist

• PR has meaningful title
• Summary describes changes
• PR is ready to be merged
  • If not, use the arrow next to Create Pull Request to mark it as a draft. PR can be marked Ready for review when it's ready.
• Tests are added/update (if required)
• Documentation is updated/added (if required)