New fsspec writing breaks for pathlib.Path

[alexander-held]

The changes introduced in #1016 (as tested via an installation of uproot5 at 28b0f7b) break the use of pathlib.Path when writing files:

import pathlib
import uproot

uproot.recreate(pathlib.Path("f.root"))

results in

Traceback (most recent call last):
  File "[...]/debug.py", line 4, in <module>
    uproot.recreate(pathlib.Path("f.root"))
  File "[...]/uproot5/src/uproot/writing/writable.py", line 148, in recreate
    sink = _sink_from_path(file_path, **storage_options)
  File "[...]/uproot5/src/uproot/writing/writable.py", line 80, in _sink_from_path
    return uproot.sink.file.FileSink.from_object(file_path_or_object)
  File "[...]/uproot5/src/uproot/sink/file.py", line 55, in from_object
    raise TypeError(
TypeError: writable file can only be created from a file path or an object

    * that has 'read', 'write', 'seek', and 'tell' methods
    * is 'readable() and writable() and seekable()'

We ran into this via nightly tests in pyhf (cc @matthewfeickert) and cabinetry.

The above still works fine in 113c58c.