from pythonx.compose.ui import modifier fails when no binder is installed #38

Found by the docs review for #34. from package import name asks the package for the attribute before it imports a submodule, and falls back only on AttributeError. The re-export getattr raised RuntimeError (binding layer not installed) for every name, so from pythonx.compose.ui import modifier failed outside an app even though ui/modifier.py is an ordinary file. Done when a submodule file is answered before anything needs the binder, a test pins it without a binder, and Kotlin names still raise the RuntimeError.