[MATLAB] Make arrow.type.TemporalType a "tag" class

[sgilmore10]

Describe the enhancement requested

The original motivation for adding the super-class arrow.type.TemporalType in #37236 was to define a common implementation for extracting the Unit property from TimestampType, Time32Type, Time64Type, Date32Type, and Date64Type. However, this approach doesn't work because the Unit property on Date32Type and Date64Type is a DateUnit, while the Unit property on the other three types is aTimeUnit. As a result, we cannot define a shared method for extracting the Unit property in TemporalType.

Instead, we plan on making arrow.type.TemporalType a "tag"-class (i.e. it has no properties or methods) so it can be used to group the "temporal" types together to ease authoring conditional logical in client code. In a future PR, we plan on adding functions like arrow.type.isTemporal, arrow.type.isNumeric, etc. so that clients don't need to query the class type information directly (i.e. call isa(type, "arrow.type.TemporalType")).

function doStuff(arrowArray)
  import arrow.*

  arrowType = arrowArray.Type;
  if type.isTemporal(arrowType)
      ...
  else if type.isNumeric(arrowType)
      ...
  else 
      ...
  end
end

Component(s)

MATLAB