conflux: Avoid non fatal assert in CIRCUIT_IS_CONFLUX()

In the circuit_about_to_free(), we clear the circ->conflux object and then we end up trying to emit an event on the control port which calls CIRCUIT_IS_CONFLUX() and non fatal assert on the false branch.

Fixes #41037 (closed)

Signed-off-by: David Goulet dgoulet@torproject.org

changed milestone to %Tor: 0.4.8.x-post-stable

requested review from @mikeperry

assigned to @dgoulet

approved this merge request

These kinds of checks were useful in tracking down various teardown bugs and races in the past.. But this seems fine to just remove now.

merged manually