Performance: do not load entities by UUID one by one

Problem/Motivation

This was extracted as a potential improvement from ✨ Export images uploaded via CKEditor Active since not just the new code but existing one would also need to refactored.

More context: https://git.drupalcode.org/project/single_content_sync/-/merge_requests/...

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes