Change BlueprintPipe size return to maxSize value.

The loophole is still there but at least we're checking the optimal
bound on the blueprint so validation is more accurate when no data
has been written yet.

Author: Lawrence

+types/+untyped/DataPipe.m

@@ -235,7 +235,7 @@
             if isa(obj.internal, 'types.untyped.datapipe.BoundPipe')
                 sz = size(obj.internal, varargin{:});
             elseif isa(obj.internal, 'types.untyped.datapipe.BlueprintPipe')
-                sz = size(obj.internal.data, varargin{:});
+                sz = obj.internal.maxSize;
             else
                 error('MatNWB:DataPipe:UnhandledPipe', ['Internal Datapipe of type `%s` does not '...
                     'have a handled size() method.'], class(obj.internal));