[Editor] Creating new project doesn't check if destination folder is empty

[PeturDarri]

Describe the bug
I was creating a new project and called it "Test", but I was unaware I had an existing Unity project with that same name in the same folder. Prowl had no issue with this, overwriting its project template files into the folder, but then errored when it tried to import a Unity asset file, breaking the editor.

To Reproduce
Steps to reproduce the behavior:

1. Create a Prowl project with the same name of an existing Unity project.
2. Observe the error log "Project at path <...> already exists.", but no notification in the editor application.
3. Observe issues when opening this project. (It depends on what assets are in the project, whether it breaks completely)

Expected behavior
The editor application notifies or prevents you from creating a project in an existing folder.