Add optional fallback parameter to AsyncSlurmFoamCase.run

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 89.20%. Comparing base (8034581) to head (aeb36a9).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #217 +/- ## ========================================== + Coverage 89.14% 89.20% +0.06% ========================================== Files 16 16 Lines 1207 1214 +7 ========================================== + Hits 1076 1083 +7 Misses 131 131 ```

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