NPA-4284: Allow api headers to be case insensitive

[ellie-bound1-NHSD]

Pull Request

Ticket Link

https://nhsd-jira.digital.nhs.uk/browse/NPA-4284

Description/Change Summary

• Added 2 python script policies
• 1 Translate Request Headers which translates Request ID and Correlation ID request headers into parcel case to be sent to client. Also store original casing of request headers.
• 2 Mirror Request Headers in the response which takes the stored original casing of request headers and adds this to the response for both successful and unsuccessful responses.

How to test?

• Deployed to internal-dev in apigee via making the changes manually, saving revision no. 174 and deploying this to internal-dev
• Ran regression tests of dev here
• Have branch with updated api tests that are passing here

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 or part of the acceptance criteria of the ticket, and the code is in a mergeable state.
• If there were infrastructure, operational, or build changes, I have made sure there is sufficient evidence that the changes will work.
• I have ensured the changelog has been updated by the submitter, if necessary.

Post-merge

After merging and deploying changes to the sandbox, Postman collection or spec examples please run theRun Postman collection workflow.

This will run the tests within the collection to check that the sandbox is working as expected once deployed.

[github-actions]

This branch is work on a ticket in the NHS Digital NPA JIRA Project. Here's a handy link to the ticket:

NPA-4284

[github-actions]

This branch is work on a ticket in the NHS Digital NPA JIRA Project. Here's a handy link to the ticket:

NPA-4284

[github-actions]

This branch is work on a ticket in the NHS Digital NPA JIRA Project. Here's a handy link to the ticket:

NPA-4284

[github-actions]

This branch is work on a ticket in the NHS Digital NPA JIRA Project. Here's a handy link to the ticket:

NPA-4284

[github-actions]

This branch is work on a ticket in the NHS Digital NPA JIRA Project. Here's a handy link to the ticket:

NPA-4284