Consider moving row height calculation from virtualizer to table (and monitoring for token changes)

[msmithNI]

🧹 Tech Debt

Currently the table virtualizer.ts computes rowHeight repeatedly when needed, based on the controlHeight and borderWidth token values. KeyboardNavigationManager also relies on row height indirectly (it uses pageSize which is a function of row height).

• Probably the table should handle that computation
• We should monitor the tokens for changes, and update the row height accordingly
• If we do the above, we need to make sure the virtualizer behaves sanely if those token values change (may or may not right now)