Fix crash in MWExtensionNode creation mode

We can't get the directionality from the focused node if there isn't one.

This doesn't add any logic to determine the directionality in creation
mode, filed https://bugzilla.wikimedia.org/show_bug.cgi?id=57421 for that.

Change-Id: I3ff8d48f19c7beef5e24b55712a26d86efa5812a
Merge "Fix crash in MWExtensionNode creation mode"