feat(DTFS2-6892): add schema tests for commonised tfm user

[AlexBramhill]

Introduction ✏️

We need to add new tests for tfm user

Resolution ✔️

The existing needed to be improved to be more scalable, this has been refactored to allow ease of use and time savings

It creates a series of chainable withSomethingTests that can be called easily via withSchemaValidationTests. It then automatically creates all required tests based on the test cases, and the supplied test case type.

It is easily extendable (all existing patterns are established), and easy to use to write tests.

  withSchemaValidationTests({
    schema: DECODED_AUTH_CODE_REQUEST_STATE_SCHEMA,
    aValidPayload,
    testCases: [
      {
        parameterPath: 'csrfToken',
        type: 'string',
      },
      {
        parameterPath: 'successRedirect',
        type: 'string',
        options: { isOptional: true },
      },
    ],
  });