slim down dependencies

[Stebalien]

Remove secio, quic, and circuit transports from testing dependencies.

• We temporarily added quic/circuit dependencies because a test needed them. But this is no longer the case.
• We introduced the secio dependency before we had a fully featured "insecure" transport for testing.

[raulk]

For SecIO, this should be fine, as adding a real secure channel does not change our code coverage. But for circuit, I was under the impression that the goal of that test was to verify that we allow the dial even if we are FD-limiter, because the circuit transport does not consume further FDs if we’re already connected to the relay?

[Stebalien]

IsFdConsumingAddr is a pure function. This test added the QUIC and circuit transports because, when it was first written, IsFdConsumingAddr looked at the registered transports themselves. But that was changed before the PR adding IsFdConsumingAddr was merged.

[Stebalien]

TL;DR: this doesn't affect code coverage.