Fix the file move in wvd add when the WVDs folder does not exist

On new installs, or where the `WVDs` folder is not made yet, then the shutil.move() assumes it's a file path and moves the `.wvd` file to the WVDs folder path, as a file. If the folder existed but was empty, this error wouldn't have occurred.

devine/commands/wvd.py

@@ -39,7 +39,7 @@ def add(paths: list[Path]) -> None:
         else:
             # TODO: Check for and log errors
             _ = Device.load(path)  # test if WVD is valid
-            shutil.move(path, config.directories.wvds)
+            shutil.move(path, dst_path)
             log.info(f"Added {path.stem}")