[experiments][ui] enhance example multiselector with `add to split` button

[axiomofjoy]

[rahulrocksn]

I would like to take on this if no one else has taken on it. Can I get some more context on it?

[axiomofjoy]

Hey @rahulrocksn, this is probably not the best ticket to pick up since it is blocking an active milestone. Please take a look at the help wanted label.