fix minio storage iterator path (#24691)

minio storage iterator shows different behavior with local fs iterator.

in local fs storage:

``` go
s.IterateObjects("prefix", func(path,obj)
     println(path) // show "prefix/xxx.file"
})
```

in minio storage:

```go
s.IterateObjects("prefix", func(path,obj)
     println(path) // show "xxx.file"
})
```

I think local fs is correct, minio use wrong `basePath` to trim storage
path prefix.

---------

Co-authored-by: Giteabot <teabot@gitea.io>

.github/workflows/pull-db-tests.yml

@@ -102,6 +102,13 @@ jobs:
           --health-retries 10
         ports:
           - 6379:6379
+      minio:
+        image: bitnami/minio:2021.3.17
+        env:
+          MINIO_ACCESS_KEY: 123456
+          MINIO_SECRET_KEY: 12345678
+        ports:
+          - "9000:9000"
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-go@v4