Integrate signature insights into the redesigned signature screens

[FrederikBolding]

We should integrate signature insights into the redesigned signature screens in extension.

Snaps UI can be shown in: https://github.com/MetaMask/metamask-extension/blob/548b54aae983ddc68af56156984f0ea49063ebed/ui/pages/confirmations/components/confirm/pluggable-section/pluggable-section.tsx#L10

For now we can treat critical severity as a flag to add to the alerts system instead of the modal we've previously used: https://github.com/MetaMask/metamask-extension/blob/develop/ui/pages/confirmations/hooks/useConfirmationAlerts.ts#L60