Fix: Make inherited read-only datasets from schema read-only properties in matnwb

[ehennestad]

Motivation

The IZeroClampSeries has three datasets (capacitance_compensation, bridge_balance, bias_current) where the value should be fixed according to the schema.

This fix ensure the values are set to zero when objects are created, and also issues a "read-only" error if users try the set another property value

How to test the behavior?

types.core.IZeroClampSeries()

The values of the datasets listed above should be 0, instead of empty ([]) as before

types.core.IZeroClampSeries('bias_current', 1)

Should now throw an error

Checklist

• Have you ensured the PR description clearly describes the problem and solutions?
• Have you checked to ensure that there aren't other open or previously closed Pull Requests for the same change?
• If this PR fixes an issue, is the first line of the PR description fix #XX where XX is the issue number?

[ehennestad]

Thanks to @stephprince for helping figuring this out

[bendichter]

I don't know if "read-only" is quite right. That would imply that it has already been written and is being read, which isn't quite true. How about "because it is a fixed value"

[ehennestad]

I am following the convention In MATLAB where properties that are Constant or has SetAccess = private/protected (i.e., users cannot set the value), are "read-only".

[ehennestad]

So with this classdef:

classdef SimpleClass
    % SimpleClass - A class with a Constant property
    
    properties (Constant)
        Name=2
    end
    methods
        % Constructor
        function obj = SimpleClass()
        end
    end
end

You will have this error if you try to set the Name property:

>> s=SimpleClass();
>> s.Name=3
Unable to set the 'Name' property of class 'SimpleClass' because it is read-only.

[bendichter]

ah, ok. I'm not crazy about that language but it's fine if it's consistent with existing MATLAB usage

[bendichter]

looks like there are some test issues from the schema update but the changes from this PR look good