Should discard calls that have an abnormally high weight.

[vgeddes]

In theory, Solidity apps could potentially send a message (dispatchable call) to our parachain with an abnormally high weight. Executing these messages could result in huge fees for the relayer, or potentially they won't be executed at all, causing the bridge to break.

In practice not so much an issue with our current system, as I have logic in the parachain to filter out any other calls other than DOTApp.unlock, ETHApp.mint and ERC20App.mint.

So in future, if we ever allow calls to other dispatchables (local or remote via XCMP), we will need to guard against the problem somehow.

[vgeddes]

This problem will be resolved by https://github.com/Snowfork/snowbridge/pull/540