Allow players to change runes/masteries/spells at start of game before leaving shop

inb4 someone says "or don't forget to change your runes/masteries/spells before the game starts aren't I clever MYEHHHH"

... Don't be that guy.

Upvote if you like. Downvote if you're that guy. sniffle

This would be particularly helpful in ARAM with all the back and forth in trade and more mixups with builds that doesn't always leave me with enough time to think picks and builds through before I end up with clarity on xin.