Better outcomes when Spans/Items are dropped because of Schema validation

[Dav1dde]

Schema validation (or other things) may turn a Annotated(Some(Span)) into Annotated(None, Error), in this case we can possibly emit a better outcome than just NoData derived from the Error.

From: https://github.com/getsentry/relay/pull/5258#discussion_r2436140392

[linear[bot]]

RELAY-167