fix(active-desendant): item scroll when not in view

[saiponnada]

Fixes #198,

Following changes were implemented

• Changed scroll behavior to smooth and set block:nearest
• Also added another check to see if the intended scrollable element in view.

Other approaches discussed but not implemented are, to check if the listbox is in expanded state. This change might require a refactor and need to use listbox directly to benefit the change.

[LuLaValva]

Looks like a good change all around! I think this is the right solution

[agliga]

Lets see if this will work correctly. It looks like a good change, but I think it might not be fixing all of our usecases
Lets try it though