fix how `filesystem` deals with windows UNC paths about dlt

[rudolfix]

we just got an update: for natively specified file paths to local filesysten ie C:\my\path if the path does not exist there's no error message. if the path exists the pipeline does not see any files. so certainly something is wrong here

[IlyaFaer]

@rudolfix, okay, I think I reproduced it:

Figuring out what's wrong there.

[IlyaFaer]

@rudolfix, I wonder what's the meaning of this line:

dlt/dlt/common/storages/fsspec_filesystem.py

Line 287 in 20664b2

bucket_url_no_schema[2:] if bucket_url_no_schema.startswith("//") else bucket_url_no_schema

[rudolfix]

@IlyaFaer this strips leading "//" from the front but IDK why.
I think this part:

# make that absolute path on a file://
        if bucket_url_parsed.scheme == "file" and not file.startswith("/"):
            file = f"/{file}"
        file_name = posixpath.relpath(file, bucket_url_no_schema)
        file_url = bucket_url_parsed._replace(
            path=posixpath.join(bucket_url_parsed.path, file_name)
        ).geturl()

destroys some of the local paths
you'll need to debug that more

[IlyaFaer]

@rudolfix, yes, I brought a couple of fixes into your code, but I see that fsspect package code is also breaking the path in some way. Checking what's wrong there yet...