Avoid re-rendering transactions table on row hover

[gustavlrsn]

Issue mentioned by @kewitz in opencollective/opencollective-frontend#10374 (comment):

I caught something while testing the performance of the Transactions dashboard: onHoverRow causes the whole table to re-render when hovering over a different group. This is fine for now because we do not display a lot of transactions in the table right now, but it could become an issue if we decide to increase the number of rows being displayed at the same time. A possible solution would be implementing this effect using CSS selectors and data properties.