authorizations: replace js client with oats generated client

Replace references to `import {client} from 'src/utils/api'` in the following files with `import {FUNCTION_NAME} from 'src/client'`

- `src/dataLoaders/components/verifyStep/FetchAuthToken.tsx`

Ensure sufficient tests are available before making the switch and that tests pass after replacement.

Start with src/dataLoaders/components/verifyStep/FetchAuthToken.tsx and inspect the current src/utils/api import and the available export from src/client. Check existing tests for this data loader or authorization flow before changing the client reference, then run those tests and confirm they pass after the replacement.

Written by the indexing model from the issue text.