Explore Datatable crash when dimension is empty

[Usiel]

Explore UI errors out when a time-series based chart is selected and one of the non-time dimensions has an empty value ''.

How to reproduce the bug

1. Load the birth_names example dataset
2. Add a calculated column called "empty" with the following expression: CASE WHEN gender = 'girl' THEN 'Girl' ELSE '' END
3. Create a chart based on the birth_names
4. Select any time-series viz type
5. Group by the new calculated dimension
6. Update Chart

Expected results

Results tab loads the results grouped by time with the calculated dimension as columns.

Actual results

Page goes blank with the following error:

react-dom.production.min.js:209 Error: A column ID (or string accessor) is required!
    at x (react-table.production.min.js:1:4204)
    at react-table.production.min.js:1:3337
    at Array.map (<anonymous>)
    at w (react-table.production.min.js:1:3313)
    at react-table.production.min.js:1:53001
    at Object.useMemo (react-dom.production.min.js:165:493)
    at t.useMemo (react.production.min.js:25:113)
    at e.useTable (react-table.production.min.js:1:52974)
    at b (TableView.tsx:151:7)
    at Ko (react-dom.production.min.js:153:146)

Environment

• superset version: 8d4994a (current master) and also 1.5.0

Checklist

Make sure to follow these steps before submitting your issue - thank you!

• I have checked the superset logs for python stacktraces and included it here as text if there are any.
• I have reproduced the issue with at least the latest released version of superset.
• I have checked the issue tracker for the same issue and I haven't found one similar.

Additional context

Reintroduced with #18569, previously fixed with #17303