Fix tests or lock foundry CI version

[dtbuchholz]

See the error in https://github.com/recallnet/contracts/actions/runs/13085476261/job/36516308102#step:8:1

The error mentions that ValidatorGater is using testFail.., which no longer exists. We use the latest nightly version in our CI, so maybe that's why it failed.

[FAIL: `testFail*` has been removed. Consider changing to test_Revert[If|When]_Condition and expecting a revert] Found 1 instances: testFailUnauthorizedApprove (gas: 0)

[dtbuchholz]

cc @avichalp

I'm not sure why this happened all of the sudden...maybe a new foundry nightly version was released between the time I pushed my latest PR (the test passed) and merged it (test failed).