Upgrade to runtime 1.23.1: Security updates

This runtime upgrade adds two security updates:

1. Disallow xcm messages containing transact as a result of the SR Labs audit
2. Allow vaults to withdraw to 0 collateral or to above the minimum collateral to prevent an incentive attack in the vault capacity model

For more details, please see the following:

https://github.com/interlay/interbtc/releases/tag/1.23.1
https://github.com/interlay/interbtc/compare/1.23.0...1.23.1

The clients do not need to upgraded for this release

The latest compatible clients release for this version is v1.20.0:

https://github.com/interlay/interbtc-clients/releases/tag/1.20.0

Request to fast-track
Due to the security nature of this proposal, we request TC fast-track.