[Explore][Table] Adding sort by without metrics causing unexpected error

[ktmud]

Expected results

Table chart should allow sort by without metrics.

Actual results

Table chart is not able to handle sort by without metrics.

Screenshots

How to reproduce the bug

1. Go create a new Table viz
2. Add a Group by column
3. Add a sort by metric
4. Run the query

Environment

Latest master and an example dataset on Postgres.

Additional context

Could be related to #13426 #13423 and #13228