Don't allow text to overflow an ambiguity button in the Y direction

Thanks to one of my nephews for submitting something like:

	b̵̩͚̽̀͂͂͑̿͘̕͝u̸̮̅͌g̷̡̢̻̬͎̙͉̳̬͈̑̐̋̃̅ẻ̶̤̜̾̐x̷̦͔͚͙̤̀̀̀̂̕ṣ̷͙̦̘̰̔̾͊̊̍̒͛̄̉̚p̵̡̤̫̹̥̀́́͆ǫ̷̮͚̳̭̘̭̏s̷͔̈́̈͋̿̌̑͛̚̚͘i̸͔͔̾̄͐̓͗͐̌͘ṉ̷̨̭̻͇̥͌̓̕g̴̢̧̖̬͈͇̻͉̯͈̅̔͛̀

in our game last night, which ended up scribbling over the rows above
and below in the judging view. This fix chops things off vertically,
(which doesn't solve the case if someone is _legitimately_ trying to
get such text to appear—we can address that case when it appears).