Concurrent Sync Worker execution can lead to data inconsistencies

[MJ1998]

Describe the bug
Recent changes in PR #2053 allow two sync workers to run concurrently.
This can lead to inconsistencies if a manual one-time sync and a periodic sync overlap.
The problem arises because both workers might attempt to upload resources in a conflicting order, potentially causing:

1. Upload of older resources before newer ones
2. Overwriting of data

Component
Fhir Engine Library

To Reproduce
Steps to reproduce the behavior:
Not sure how to reproduce as it requires concurrent running of the workers to sync resources that can cause inconsistency.

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
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Smartphone (please complete the following information):

• Device: [e.g. Pixel4a emulator]
• Android version: [e.g. Settings -> About phone -> Android version]
• Build number: [e.g. Settings -> About phone -> Build number]
• Version [e.g. 22]

Additional context
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