Merge topic 'AddPackLabelsFilter'

f3f99fac Fixed different type comparison
9fa17cdb Extended test to process cell data
ee4c8963 Feature to sort labels based on the label value, or frequency of occurrence
b57965fc Issue warning when no input scalars are found
75582d62 Added warning to indicate packing into small data type
4632356c Changed auto declaration to use proper type for large data.
2b37c102 Generalized the filter to accept vtkDataSet on input
f11b6118 Added flags to controls passing of input point, cell, field data to the output
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Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: buildbot <buildbot@kitware.com>
Merge-request: !10126