Fix middleware unused AuthenticationFailed

[jerryfletcher21]

What does this PR do?

Simply remove an unused import that is failing linters.

Checklist before merging

• [x] Install pre-commit and initialize it: pip install pre-commit, then pre-commit install. Pre-commit installs git hooks that automatically check the codebase. If pre-commit fails when you commit your changes, please fix the problems it points out.

[Reckless-Satoshi]

Thank you @jerryfletcher21 , looks like a possible mistake on a merge conflict resolution I did yesterday on #1242