Support ordering XCom entries in the REST API and UI

[yuseok89]

fixes: #64594

There is already an open PR for this issue and review had started, but the original author has had no activity for roughly a week, so I prepared this change in parallel so the work does not stall.
Please treat this as optional: if maintainers prefer to wait for the original PR, you may close this one without concern. If the original author returns and their PR moves forward, closing this PR is fine on my side. I am not trying to block their contribution.

This PR adds server-side ordering for the XCom list REST API and wires column sorting on Browse → XComs to that API, in line with other DataTable + order_by usage in the codebase.

Demo

Screen.Recording.2026-04-17.at.10.11.12.PM.mov

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