Clear constraint check status after simulating

[duranb]

resolves #1320

To test:

1. Create a plan
2. Create a constraint Ex: export default function peelGreaterThanOrEqual3(): Constraint { return Real.Resource('/peel').greaterThanOrEqual(3); }
3. Add constraint to the plan
4. Add activities relevant to constraint
5. Check constraints
6. Run simulation
7. Verify that the previous constraint check status is now marked as "unchecked" in the nav bar and constraint panel