Move Entity Loading and Lookup into Helper Service

Problem/Motivation

Currently, a lot of logic for loading and examining entities is included in the the central ContentLoader class. As this develops further it continues to expand the dependencies and requirements injected into the class, also making testing difficult to achieve effectively.

Having this logic buried within the ContentLoader class also makes it inaccessible in other places that might benefit from the same lookups and loading as described in these related issues:

• #2893055: Expand logic for identifying content to update
• #2879468: Nodes Cannot Create Menu Links Automatically
• #2894614: Allow configuration of properties used to match existing entities
• #2876203: Support load user entity by name process callback
• #2917940: Change reference callback to load entity directly

Proposed resolution

Extract logic to interact directly with entity definitions and storage handlers into a separate helper service to reduce redundancy and tight coupling of services that is making effective unit testing difficult. Using this separation of dependencies, more unit testing should be added to confirm existing functionality within the ContentLoader class.

Remaining tasks

1. Create and extract entity logic into new EntityLoadHelper service
2. Refactor required services and related loading of these dependencies to better support mocking in unit tests
3. Implement unit tests to confirm existing functionality
4. Extend usage of new service and features into related tickets

API changes

• Introduce new EntityLoadHelper service
• Update ContentLoader dependency injection requirements
• Refactor existing unit tests

Data model changes

TBD