VED-240: Handle-PDS-Rate-Limit

[Akol125]

Summary

• Routine Change
  Implemented improved HTTP error handling and retry logic for PDS client integration to support clearer failure diagnostics and resilience against transient downstream failures.

Also made the mns error handling function reusable and moved to shared, so it can be re-used for PDS

Reviews Required

• Dev
• Test
• Tech Author
• Product Owner

Review Checklist

ℹ️ This section is to be filled in by the reviewer.

• I have reviewed the changes in this PR and they fill all of the acceptance criteria of the ticket.
• If there were infrastructure, operational, or build changes, I have made sure there is sufficient evidence that the changes will work.
• If there were changes that are outside of the regular release processes e.g. account infrastructure to setup, manual setup for external API integrations, secrets to set, then I have checked that the developer has flagged this to the Tech Lead as release steps.
• I have checked that no Personal Identifiable Data (PID) is logged as part of the changes.

[github-actions]

This branch is working on a ticket in the NHS England VED JIRA Project. Here's a handy link to the ticket:

VED-240

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
97.6% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[dlzhry2nhs]

Nice work. Thanks for all the changes.

[dlzhry2nhs]

Nice work. Thanks for all the changes.

Also please mention to @mfjarvis in standup that you moved some files around. Believe he was looking at improving the authentication part for the performance tests.

[dlzhry2nhs]

Nice work. Thanks for all the changes.

Also please mention to @mfjarvis in standup that you moved some files around. Believe he was looking at improving the authentication part for the performance tests.

To be clear, this does not mean block the PR. You have had 2 reviews so can merge if you like. I was just saying that we should give Matt a heads up about this change; which we did in standup.