Table: Automatically detect JSON cells

Originally added in https://github.com/grafana/grafana/pull/81152, and removed in https://github.com/grafana/grafana/pull/91862, users have expressed a desire for the "correct" inspector tab by default. The next version of the table should show the code mode where appropriate, so users dealing with JSON in a table don't need to manually change tabs every time they inspect a cell.