chore(3p/nix): don't optional-wrap EvalState::file_access_trace_fn further r/1616

std::function has a natural null we can't eliminate anyway, so this was
effectively std::optional<std::optional<non_nullable_function>>.

Change-Id: If99f139146021edb25d133dad7f0f6e125ef53df
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1688
Tested-by: BuildkiteCI
Reviewed-by: kanepyork <rikingcoding@gmail.com>
Reviewed-by: glittershark <grfn@gws.fyi>

0 files changed, 0 insertions, 0 deletions