Issue Description

Currently, replay on backend error is limited, when the replay isn't yet sampled.

• Improve Session Replay integration with server rendered HTML pages (MPAs) sentry-javascript#9490

But when the replay is already recording when the request is done to the backend, we can send that replay_id in the baggage header. Allowing for any events captured by the backend SDK to include it in the DSC. This should allow

Reproduction Steps

Add replay to the FE with replaysSessionSampleRate set to 1.0.
Cause an error on the BE when serving the request.

Expected Behavior

Replay attached to the BE error

Actual Behavior

no replay on the BE error.

Ruby Version

3.3.4

SDK Version

5.18.2

Integration and Its Version

No response

Sentry Config

No response