Updating my node version to v16, I noticed many tests breaking, because
the way errors are formatted did change. This commit ensures that the
test suite keeps working for all node versions.
In most cases, we just want Component<any, Env>. But since it was so
annoying to have always the type Env, we actually used
Component<any,any> everywhere.
With this commit, the generic types have a default (and their order is
swapped), so we can simply use Component in most cases, and
Component<Props> when we want to type the props.