arrow

GH-37591: [MATLAB] Make `arrow.type.Type` inherit from `matlab.mixin.Heterogeneous` (#37593)



### Rationale for this change

We should modify `arrow.type.Type` to inherit from `matlab.mixin.Heterogeneous` so that it's possible to create a nonscalar array containing different concrete subclasses of `arrow.type.Type`. 

**Example**
```matlab
>> float32Type = arrow.float32();
>> timestampType = arrow.timestamp(TimeZone="Pacific/Fiji");
>> typeArray = [float32Type timestampType]

typeArray = 

  1×2 heterogeneous FixedWidthType (Float32Type, TimestampType) array with properties:

    ID
```

Currently, running the example above results in an error:

```matlab
>> float32Type = arrow.float32();
>> timestampType = arrow.timestamp(TimeZone="Pacific/Fiji");
>> typeArray = [float32Type timestampType]
Error using horzcat
The following error occurred converting from arrow.type.TimestampType to arrow.type.Float32Type:
Invalid argument at position 1. Value must be of type libmexclass.proxy.Proxy or be convertible to libmexclass.proxy.Proxy.
```

### What changes are included in this PR?

1. Updated `arrow.type.Type` to inherit from `matlab.mixin.Heterogeneous`. Previously, it only inherited from `matlab.mixin.CustomDisplay`.
2. Because `arrow.type.Type` is now `heterogeneous`, its subclasses cannot override the protected method `getPropertyGroups` - which is inherited from `matlab.mixin.CustomDisplay`. This method must be `Sealed` and defined on `Type` because only `Sealed` methods can be called on nonscalar `heterogeneous` arrays. To get around this limitation, I defined a new abstract template method called `getDisplayPropertyGroups`, which `getPropertyGroups` invokes if the array is either scalar or nonscalar and `homogeneous`. Refer to [this link](https://www.mathworks.com/help/matlab/matlab_oop/custom-display-for-heterogeneous-arrays.html) for more details. 

**Displaying a nonscalar *heterogeneous* `arrow.type.Type`**

```matlab
>> float32Type = arrow.timestamp(TimeUnit="Second");
>> timestampType = arrow.timestamp(TimeZone="Pacific/Fiji");
>> typeArray = [float32Type timestampType]

typeArray = 

  1×2 heterogeneous FixedWidthType (Float32Type, TimestampType) array with properties:

    ID
```

**Displaying a nonscalar *homogeneous* `arrow.type.Type`**

```matlab
>> timestampType1 = arrow.timestamp(TimeUnit="Second");
>> timestampType2 = arrow.timestamp(TimeZone="Pacific/Fiji");
>> typeArray = [timestampType1 timestampType2]

typeArray = 

  1×2 TimestampType array with properties:

    ID
    TimeUnit
    TimeZone
```

### Are these changes tested?

Yes

1. Added a new test class in `test/arrow/type` called `tDisplay.m` 
2. Added display unit tests for all concrete subclasses of `arrow.type.Type` if they did not already exist. 
3. Added a new test class in `test/arrow/type` called `tIsEqual.m`. This class contains unit tests verifying the `isequal` method of `arrow.type.Type` behaves as expected when called on heterogeneous arrays.

### Are there any user-facing changes?

Yes. Users can now create nonscalar  arrays with different concrete subclasses of `arrow.type.Type`.

### Future Directions

1. Move all display unit tests to `tDisplay.m`
2. Add an `arrow.type.NumericType` class from which all numeric types inherit. This class will define `getDisplayPropertyGroups` for all numeric types.

* Closes: #37591

Authored-by: Sarah Gilmore <sgilmore@mathworks.com>
Signed-off-by: Kevin Gurney <kgurney@mathworks.com>