[bugfix] ygg funds when total value is more than 25%

There is a fast-exit in determining if we should fund a Yggdrasil. If the total vault value is great than 25% of their bond. This can be a problem where one asset goes to zero in their vault, while the other assets are still plentiful. We can no longer use that vault for this missing asset anymore.

Instead, we now evaluate each coin to check if its total number of coins is less than half of what it should be.