[PRMP-386] Allow bulk upload to have parallel executions

[PedroSoaresNHS]

…hs number

Description

Updated the way messages are added to the FIFO queue so that they are in different groups allowing for several simultaneous lambda executions
https://nhsd-jira.digital.nhs.uk/browse/PRMP-386

Context

This change was required since we were only having 1 lambda running at a time

Checklist

• I have followed the code style of the project.
• I have added tests to cover my changes.
• I have updated the documentation accordingly.
• I have considered the cross-team impact when creating this PR and where possible written tests to validate for all affected.
• I have built a sandbox with code from this PR and ensured the unit tests and end-to-end tests have run successfully.
• A member of all teams has approved this PR if there is a major code change. (If this is a minor change and you are confident this is not necessary then you may accept the standard approval process of 2 approvals from any teams.)

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud