Question: Shape constraint for TimeSeriesReferenceVectorData?

[ehennestad]

Currently the TimeSeriesReferenceVectorData can have any shape allowed by VectorData, so it can be 1D to 4D. However, it seems like it should be constrained to a 1D shape, i.e by adding the following to its spec:

dims:
  - n_refs        # or num_rows when used as a DynamicTable column
shape:
  - null          # 1-D, variable length

[oruebel]

However, it seems like it should be constrained to a 1D shape

That is how it is currently being used. I can see use-cases where one would want multiple references per row in a table, but probably as a ragged column (via VectorIndex), which would also just require a 1D shape for TimeSeriesReferenceVectorData. I think the safest route would be to restrict the shape of TimeSeriesReferenceVectorData in the specific places it is being used, e.g., add shape to the timeseries column in TimeIntervalsTable and the respective columns in the IntracellularRecordingsTable. However, if it makes code maintenance easier, then I think it is in also fine to restrict TimeSeriesVectorData itself to be 1D, since that still covers all our current uses and I think should cover most future uses. @rly thoughts?