Sanic.get_app with no app name

[ahopkins]

Is your feature request related to a problem? Please describe.

Sometimes you want to get the app instance, but do not have the name of the app.

app = Sanic.get_app("what was it called again 🤔")

Describe the solution you'd like

    @classmethod
    def get_app(cls, name: Optional[str], *, force_create: bool = False) -> "Sanic":
        # If name is None, then return the first item in the app registry

Additional context

See docs