fix(web): change element wrapping core/EmptyState children

[dgdavid]

Problem

The elements in the login page are rendered wrongly since #1441. That's because the Flex component used for wrapping the core/EmptyState children. It is missing the "direction" prop for telling it to layout children vertically instead of horizontally. Moreover, it looks like a Stack element is a better choice for this case.

Solution

Adapt core/EmptyState for using an <Stack hasGutter> instead of a <Flex> configured to behave almost the same.

Testing

• Tested manually

Screenshots

Before	After