Infer Promise results to toast styles

[MarioP-Dev]

When using a Toast with a Promise, it would be very helpful to infer the result of the promise to the styles of the toast.

For example:

• When the promise is loading, loading state should be used (as it works now).
• When the promise finished without errors, severity: success and color: success
• When the promise finished with errors, severity: error and color: error

[Dan6erbond]

Really would like to see this, ideally the toast should also use the icon only after the promise resolves, right now setting an icon overrides the loading spinner (for which I'd argue is what we have the loadingIcon for).