upate copy path to correctly handle files that contain the word public

[jacoblogan]

The copy function isn't working with filenames or paths that contain the word public. Instead of just taking the part of the path found after the last instance of the word public this change will take everything after the first instance found.

[Niels-IO]

Thanks for the catch @jacoblogan. I will take a look!

[Niels-IO]

@jacoblogan Thanks for the PR. I merged it with a slight edge case handling when public is not found at all