further fixes after change 31470

- get_module is to be called when io is autocreated
- register_module is missing in playground

Change-Id: I28884575b71320667107c494473b0fc5d4363a50
Reviewed-on: https://forge.frm2.tum.de/review/c/secop/frappy/+/32123
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Alexander Zaft <a.zaft@fz-juelich.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>

frappy/io.py

@@ -63,6 +63,7 @@ class HasIO(Module):
                 io = self.ioClass(ioname, srv.log.getChild(ioname), opts, srv)  # pylint: disable=not-callable
                 io.callingModule = []
                 srv.modules[ioname] = io
+                srv.dispatcher.register_module(io, ioname)
                 self.ioDict[self.uri] = ioname
             self.io = ioname