The two TestAuxiliaryClientPoisonedCacheEviction tests were written
when explicit-provider users got no fallback at all on connection
errors — they asserted ConnectionError propagated after eviction
because the fallback gate blocked the auto chain.
After the #26803 fix in the previous commit, capacity errors
(payment/quota/connection) now DO trigger fallback even on explicit
providers. The tests still verify cache eviction (their actual
contract) but now stub _try_payment_fallback so the fallback
machinery does not attempt a real network call.
teknium1
ec096cfbd8