Our extension packaging backend creates a symlink for .npm-workspaces,

but the implementation managing it had a bug in cases where we're

potentially doing things multiple times.
In our case, the Power Pack wheel gets built repeatedly for different

Python versions. After the first build, we clean up the tree, leaving

the workspaces link dangling. In this case, the call to .exists()

returns False, but the symlink is still there, and we'll fail when

attempting to create it again.
The fix is to check first if it's a symlink and unlink, and then

otherwise check if there's something present which is not a symlink.

Did a test build of an extension.