Fix toast icon to prevent clipping
Fix toast icon to prevent clipping

This fixes the bottom and right edges of the toast icon, which were getting
clipped away.

Fixes https://github.com/vector-im/riot-web/issues/11915

matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk