Decoupling Database Access in FHIR Patch Generation

[MJ1998]

To ensure all database operations originate from the FhirEngineImpl class, the synchronization functions should be refactored. Instead of directly accessing the database within the PatchGenerator class, the lambda functions used in the synchronization process should be modified to accept a List<LocalChangeResourceReference> object as input. This list will contain references to the resources that require synchronization, allowing FhirEngineImpl to handle the necessary database interactions.

This approach centralizes database access in FhirEngineImpl, improving code organization and maintainability.

IMPORTANT: All PRs must be linked to an issue (except for extremely trivial and straightforward changes).

Fixes #[issue number]

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• I have read and acknowledged the Code of conduct.
• I have read the Contributing page.
• I have signed the Google Individual CLA, or I am covered by my company's Corporate CLA.
• I have discussed my proposed solution with code owners in the linked issue(s) and we have agreed upon the general approach.
• I have run ./gradlew spotlessApply and ./gradlew spotlessCheck to check my code follows the style guide of this project.
• I have run ./gradlew check and ./gradlew connectedCheck to test my changes locally.
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[jingtang10]

Fantastic work! Thanks!