Auto expanding height #3122
Description
You can set a height when you add a row to the DataTable, but there is currently no way to make it expand to fit the content.
I think that add_row should grow an option to automatically calculate the optimal height of a row.
If we make this the default, we should be able to explicitly override it with a height. Perhaps a height of None means auto-detect, and a integer sets it explicitly. An explicit height will be faster, which might be significant if the user adds a lot of rows.