Flake: Test/BlockingPickSCNotReady

[arjan-bal]

Sample failure: https://github.com/grpc/grpc-go/actions/runs/10423722599/job/28871010600?pr=7520

Logs:

testresolverbalancerinteraction
--- FAIL: Test (10.49s)
    --- FAIL: Test/BlockingPickSCNotReady (0.05s)
        tlogger.go:116: INFO picker_wrapper.go:195 [core] blockingPicker: the picked transport is not ready, loop back to repick  (t=+369.26µs)
        tlogger.go:116: INFO picker_wrapper.go:195 [core] blockingPicker: the picked transport is not ready, loop back to repick  (t=+589.022µs)
        tlogger.go:116: INFO picker_wrapper.go:195 [core] blockingPicker: the picked transport is not ready, loop back to repick  (t=+1.069343ms)
        tlogger.go:116: INFO picker_wrapper.go:195 [core] blockingPicker: the picked transport is not ready, loop back to repick  (t=+1.363633ms)
        tlogger.go:116: INFO picker_wrapper.go:195 [core] blockingPicker: the picked transport is not ready, loop back to repick  (t=+1.517209ms)
        picker_wrapper_test.go:153: bp.pick returned non-nil error: rpc error: code = Canceled desc = received context error while waiting for new LB policy update: context canceled