imwayland: Connect OSK activating gesture to parent widget on editables
The gesture as connected currently on the child GtkText is easily overridden by the parent editables (and gently done so in the attempt to consume all clicks).
Connect this gesture to the parent editable widget in these cases, so the gesture can cohabit with the click-consuming one. It's not part of the same group, but it won't be abruptly cancelled.
Fixes: #4795 (closed)