Wire MessageBus reply traces through conditional Put pipeline

`CheckCondition::Outcome` now exposes the resulting trace (if any)
of the operations that were sent as part of the condition probe.
The outcome-accessor is changed to return a non-const reference to
allow for moving away the trace payload and into a higher-level
reply.

Turns out GetOperation did not aggregate reply traces as expected,
and PersistenceMessageTrackerImpl did not transfer trace state upon
failures (only success case). This makes this commit bigger than
initially expected, but trace coverage should now be improved on a
general basis, not just for conditional Put operations.

0 files changed, 0 insertions, 0 deletions