Consider removing the paths argument to discover()

[tlambert03]

paths is there to allow discovery of plugins that are not in sys.path (by temporarily adding the specified paths to sys.path, just for the duration of discovery) ...
while it works for discovery, it's rather error prone later because of all of our usage of delayed imports and python_name. Unless the manifest somehow remembers that it came from somewhere outside of sys.path, it will break at import time, and I think it's a YAGNI feature anyway