Fix issue with concurrent import of plotly module and checking permissions

[alexnirvan]

Issue raises when _permissions() is called concurrently (Ex.: in case of concurrent import plotly from two different processes or scripts):

• open TEST_FILE on a second call would raise an exception and _files_permissions would potentially wrongfully set to False.

[jonmmease]

Closing as this issue has been resolved by #1195 and released in version 3.3.0. Feel free to open a new issue if you're still having trouble. Thanks!