Add an option to the in-game leaderboard to keep it always expanded

[SupDos]

Now that the in-game leaderboard has been made a skinnable element, it would be great to have an option which keeps it expanded at all times, instead of contracting during gameplay

Edit: just saw there was already a discussion made for this: #22040

[yeahirai]

Relevant since the recent changes to the leaderboard

[peppy]

#33630