Changes from adding authentication to object-storage-api

[joelvdavies]

Description

Applies same changes made in https://github.com/ral-facilities/object-storage-api/pull/58. Once https://github.com/ral-facilities/inventory-management-system-api/issues/377 is done we should be able to remove the outer most conftest.py.

Testing instructions

Add a set up instructions describing how the reviewer should test the code

• [ ] Review code
• [ ] Check Actions build
• [ ] Review changes to test coverage

Agile board tracking

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 97.87%. Comparing base (7b89d00) to head (a13522a). Report is 2 commits behind head on develop.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #408 +/- ## ======================================== Coverage 97.87% 97.87% ======================================== Files 41 41 Lines 1504 1504 ======================================== Hits 1472 1472 Misses 32 32 ```

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