fix(storage-s3, storage-azure, storage-gcs): client uploads when a collection has `prefix` configured (#11436)

### What?
Fixes client uploads when storage collection config has the `prefix`
property configured. Previously, it failed with "Object key was not
found".

### Why?
This is expected to work.

### How?
The client upload handler now receives to its props `prefix`. Then it
threads it to the server-side `staticHandler` through
`clientUploadContext` and then to `getFilePrefix`, which checks for
`clientUploadContext.prefix` and returns if there is.

Previously, `staticHandler` tried to load the file without including
prefix consideration.

This changes only these adapters:
* S3
* Azure
* GCS

With the Vercel Blob adapter, `prefix` works correctly.