APPT-1893 LastUpdatedBy integration tests and custom httpClient refactor

[jsed-nhs]

Description

Replace All - 'Http' with 'GetHttpClientForTest' in all integration tests. This allows test setup to define their own api user with certain permissions. This helps confirm the lastUpdatedBy value updates between users. Also helps future testing flexibility.
Usage:
And I register and use a http client with details

  | User Id  | Role                         | Scope  |
  | mya_user | system:integration-test-user | global |

Add - Availability, Booking, Site, and Eula 'LastUpdatedBy' integration tests, with more to add in future if needed.

Ability to generically test any document with:
[Then("the '(.+)' document with id '(.+)' and partition '(.+)' has lastUpdatedBy '(.+)'")]

Added new Base method: FindSingleItemWithRetryAsync to help find cosmos documents written by separate processes.

Checklist:

• My work is behind a feature toggle (if appropriate)
• If my work is behind a feature toggle, I've added a full suite of tests for both the ON and OFF state
• The ticket number is in the Pull Request title, with format "APPT-XXX: My Title Here"
• I have ran npm tsc / lint (in the future these will be ran automatically)
• My code generates no new .NET warnings (in the future these will be treated as errors)
• If I've added a new Function, it is disabled in all but one of the terraform groups (e.g. http_functions)
• If I've added a new Function, it has both unit and integration tests. Any request body validators have unit tests also
• If I've made UI changes, I've added appropriate Playwright and Jest tests
• If I've added/updated an end-point, I've added the appropriate annotations and tested the Swagger documentation reflects the change

[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

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