commands/airspace: Remove broken `ReadingError` import
commands/airspace: Remove broken `ReadingError` import

skylines-project/skylines,RBE-Avionik/skylines,Turbo87/skylines,Turbo87/skylines,skylines-project/skylines,RBE-Avionik/skylines,RBE-Avionik/skylines,Harry-R/skylines,RBE-Avionik/skylines,Harry-R/skylines,Turbo87/skylines,Harry-R/skylines,Turbo87/skylines,Harry-R/skylines,skylines-project/skylines,skylines-project/skylines