Retain original and updated bed request values (unit/room/level of care) for reporting

When using reports to compare bed request information over the life of a transport, for example, a report meant to show when a patient's bed assignment changed between the initial bed request and the final one (different unit, room, or level of care).

Added both the "Earliest" and "Latest" versions of the Bed Request Unit and Bed Request Room fields to the report expecting to see the original value in one column and the final value in the other. Instead, both columns always show the same (latest) value, even on trips where we know the bed assignment changed.

This is because the system only keeps the current bed request value, when an updated bed request comes through from Epic, it replaces the prior value rather than being stored alongside it. The earlier value is visible in the request's activity log but is not available to reports.

Request: Retain prior bed request values (unit, room, bed, level of care) when updates are received, and make them available in reporting so "Earliest" and "Latest" return the original and most recent values respectively, consistent with how those options work for timestamps.

Why it matters: Bed changes between the initial request and patient arrival drive rework for our teams and are something we're actively trying to measure and reduce, particularly for pediatric transports where level-of-care differences matter. Without the original value, we can't quantify how often changes happen or where.