Move files_handler_params default from FileContentsManager to ContentsManager

[MaicoTimmerman]

This PR moves the default files_handler_params from FileContentsManager to ContentsManager to match.

In
https://github.com/jupyter-server/jupyter_server/pull/1069/files#diff-4d8c8c45026f674a455c1e41558c6a9a05d8766adc81a6e56d8cafc7e5d8077cR17 the web.StaticFileHandler was introduced as superclass to FilesHandler. This requires all subclasses of ContentsManager (e.g. a version for S3) to fail serving the file due to:

    Traceback (most recent call last):
      File "/home/bigdata/venv/lib64/python3.11/site-packages/tornado/http1connection.py", line 278, in _read_message
        delegate.finish()
      File "/home/bigdata/venv/lib64/python3.11/site-packages/tornado/httpserver.py", line 399, in finish
        self.delegate.finish()
      File "/home/bigdata/venv/lib64/python3.11/site-packages/tornado/routing.py", line 268, in finish
        self.delegate.finish()
      File "/home/bigdata/venv/lib64/python3.11/site-packages/tornado/web.py", line 2399, in finish
        self.execute()
      File "/home/bigdata/venv/lib64/python3.11/site-packages/tornado/web.py", line 2421, in execute
        self.handler = self.handler_class(
                       ^^^^^^^^^^^^^^^^^^^
      File "/home/bigdata/venv/lib64/python3.11/site-packages/tornado/web.py", line 238, in __init__
        self.initialize(**kwargs)  # type: ignore
        ^^^^^^^^^^^^^^^^^^^^^^^^^
    TypeError: StaticFileHandler.initialize() missing 1 required positional argument: 'path'