Export location picker defaults to `{dataset_dir}.n5`

[btbest]

When going to Export image settings, choose n5 as export format. Click Select next to file name. The file picker opens at dataset_dir, but also has the default file name {dataset_dir}.n5:

If the user now just accepts, they will get a file path like C:\Users\me\project\raw_data\{dataset_dir}.n5, which if actually used expands to an invalid export path on Windows (C:\...C:\...), but on UNIX would probably give an undesirable valid path (/home/user/.../home/user/...).

Not a big issue - the user clearly already knows where to edit the path; though it might be a bit obscure to figure out why the path is invalid/off.