Modules are designed to be individual application components, and nothing outside the module should have a need to access anything in it, which would create tight coupling, a bad design practice.
If you need to access the module, the preferred way is to use an HMVC call. So have your app controller call a module controller, and have that return the module's blog config. Ideally through a route, so you can alter the route if you later decide to design a new blog module. Your HMVC call should also be in a try/catch block, to capture an HttpNotFoundException when you are ever in a situation where you will not have a blog module installed.
If you don't care about all that, you can prefix the config name with the namespace to load a config file explicitly from that namespace. In this case that would be
Donate
