Unhandled exception when there are only backends with prefixes

[sergey-burkov-trailstone]

          +-+---------------- 1 ----------------
| Traceback (most recent call last):
|   File "/home/sburkov/.virtualenvs/tscs-v2/lib/python3.10/site-packages/starlette/middleware/base.py", line 106, in __call__
|     response = await self.dispatch_func(request, call_next)
|   File "/home/sburkov/.virtualenvs/tscs-v2/lib/python3.10/site-packages/cashews/contrib/fastapi.py", line 72, in dispatch
|     with context, max_age(cache_control_value), self._cache.detect as detector:
|   File "/home/linuxbrew/.linuxbrew/opt/[email protected]/lib/python3.10/contextlib.py", line 135, in __enter__
|     return next(self.gen)
|   File "/home/sburkov/.virtualenvs/tscs-v2/lib/python3.10/site-packages/cashews/wrapper/disable_control.py", line 36, in disabling
|     self.disable(*cmds, prefix=prefix)
|   File "/home/sburkov/.virtualenvs/tscs-v2/lib/python3.10/site-packages/cashews/wrapper/disable_control.py", line 29, in disable
|     return self._get_backend(prefix).disable(*cmds)
|   File "/home/sburkov/.virtualenvs/tscs-v2/lib/python3.10/site-packages/cashews/wrapper/wrapper.py", line 41, in _get_backend
|     backend, _ = self._get_backend_and_config(key)
|   File "/home/sburkov/.virtualenvs/tscs-v2/lib/python3.10/site-packages/cashews/wrapper/transaction.py", line 36, in _get_backend_and_config
|     backend, config = super()._get_backend_and_config(key)
|   File "/home/sburkov/.virtualenvs/tscs-v2/lib/python3.10/site-packages/cashews/wrapper/wrapper.py", line 38, in _get_backend_and_config
|     raise NotConfiguredError("Backend for given key not configured")
| cashews.exceptions.NotConfiguredError: Backend for given key not configured

Originally posted by @sergey-burkov-trailstone in #218 (comment)

[sergey-burkov-trailstone]

The exception is occurring by using CacheRequestControlMiddleware and CacheDeleteMiddleware.
CacheEtagMiddleware is not configured/used.

[Krukov]

Was fixed in 7.2.0