The ui object is created during MeshcoreDemodGUI and MeshtasticDemodGUI
construction and remains valid for the lifetime of the widget. Remove
the unnecessary null check to avoid misleading static analysis tools
into assuming ui can be null.
This resolves a Coverity false positive where the later call to
updateDechirpModeUI() was reported as a possible null dereference
in both places.
Signed-off-by: Robin Getz <rgetz503@gmail.com>