improve time handling for datasets with 1 timestep
requested to merge utkarsh.ayachit/paraview:19777-time-display-is-wrong-for-dataset-with-one-timestep into master
We now respect time values for datasets with just 1 timestep. vtkFileSeriesReader reports single timestep as normal. Similarly, vtkSMAnimationScene uses single timestep to update animation range as appropiate. In past, it would just ignore single timesteps.
Fixes #19777 (closed)
Closes #19777 (closed)