Editting start/end times of VTODOs using only the keyboard did not
trigger a check whether the VTODO is dirty. If other fields were updated
along with start/end times, everything was fine, but only editting those
times was simply ignored. The patch causes a dirty check for keyboard
edits of the corresponding KTimeComboBoxes.
BUG: 391769
FIXED-IN: 5.9.3