gridbot amount edit fail shouldn't stop the bot

[tcurtin]

Current behavior: When attempting to edit a currently running gridbot, if the amount is too high there's a warning message and the only option is to ok out of it, at which point the bot is already taken offline and orders have been pulled.

Desired: tell the user what the maximum allowed input without killing the bot is. Or at least, if the amount is too high warn the user but leave the bot unedited. Otherwise you've got a user with an active bot successful enough to want to put more money in, and that's the perfectly wrong time to pull all of its orders and make the user:

1. go through search to find it again
2. guess at the right price until it doesn't error out
3. edit the bot prices
4. go find the bot in the list again
5. click to turn it back on.

(That's 5 steps, many of which are or can take multiple actions, all happening in a panic.)