Fix silent failure when digging unbreakable blocks

[BBpezsgo]

The bot.digTime function returns Infinity if the bot cannot break the block (such as "bedrock" or "barrier"), but if you pass Infinity to setTimeout it will produce the following warning:

TimeoutOverflowWarning: Infinity does not fit into a 32-bit signed integer.
Timeout duration was set to 1.

This will result in a silent failure and the bot.dig function will resolve.

With this change, it will throw an error in such cases.

[BBpezsgo]

This will still fail if the dig time is more than 2147483647 milliseconds, but Infinite is more readable than that.