Side Peak Layout: support arrow up/down for scrolling through the table

Thanks devs for the nice Side Peak Layout in Collections!
It's also nice the the arrow left/right keys scroll the narrowed area of the table. Good work! 👍

What I miss, is the meaningful function for the arrow up/down keys. Pressing these keys, should jump to the next or previous entry in the table.
At the moment, the user needs to click with the mouse each time he wants to see the next entry.