Update terrain blanking

[marchdf]

Summary

Update terrain blanking so that the ghost cells are not tagged as blanked. This ensures only the actual part of the blanking gets tagged for refinement and not the whole bottom domain.

Tagging now looks like:

Pull request type

Please check the type of change introduced:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

Checklist

The following is included:

• new unit-test(s)
• new regression test(s)
• documentation for new capability

This PR was tested by running:

• the unit tests
  • on GPU
  • on CPU
• the regression tests
  • on GPU
  • on CPU