Allow sharing multiple examples from URL when launching LIT.
Allow sharing multiple examples from URL when launching LIT.

The sync is one way. LIT still only syncs primary selection back to URL.

PiperOrigin-RevId: 368476811

PAIR-code/lit,pair-code/lit,PAIR-code/lit,pair-code/lit,pair-code/lit,PAIR-code/lit,pair-code/lit,pair-code/lit,PAIR-code/lit,PAIR-code/lit