SDK: Token refresh failed with concurrent requests

[lubrst]

Describe the Bug

Scenario (see also #12636):

1. A page of my vuejs webapp is open until the access token expires.
2. Then a router link is clicked. Multiple simultaneous api requests are executed.
3. The refresh request is triggered, but other requests fail with 403, because authorization header is empty.

The SDK is not waiting while a refresh is running.

I have a possible solution and will link a pull request.

To Reproduce

Perform multiple requests with the SDK with expired access token.

Errors Shown

No response

What version of Directus are you using?

9.8.0

What version of Node.js are you using?

16.14.2

What database are you using?

Postgres 14

What browser are you using?

Chrome, Edge, Firefox

How are you deploying Directus?

Docker