[ty] Ecosystem checks: activate running on 'manticore' (#17916)
## Summary
This is sort of an anticlimactic resolution to #17863, but now that we
understand what the root cause for the stack overflows was, I think it's
fine to enable running on this project. See the linked ticket for the
full analysis.
closes #17863
## Test Plan
Ran lots of times locally and never observed a crash at worker thread
stack sizes > 8 MiB.
