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>

modules/storage/minio_test.go

@@ -0,0 +1,18 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package storage
+
+import (
+	"testing"
+)
+
+func TestMinioStorageIterator(t *testing.T) {
+	testStorageIterator(t, string(MinioStorageType), MinioStorageConfig{
+		Endpoint:        "127.0.0.1:9000",
+		AccessKeyID:     "123456",
+		SecretAccessKey: "12345678",
+		Bucket:          "gitea",
+		Location:        "us-east-1",
+	})
+}