Track errors when recording spans

[ChimeraCoder]

Summary

If we're encountering an error when recording a span, we want to know about it! This helps us catch situations like dropping spans due to the channel buffer being full.

Motivation

Test plan

Rollout/monitoring/revert plan

r? @asf-stripe cc @stripe/observability

[stripe-ci]

Gerald Rule: Copy Observability on Veneur and Unilog pull requests

cc @stripe/observability cc @stripe/observability-stripe