`@margin-horizontal-search` is used for margin of search component
and for personal tools, but they are also floated right so one only
gets a clearer picture of this change when the canvas is exactly at
one specific size.
Additionally it's used for a media query, so the min-width is slightly
reduced (by 32px equivalent) as well. That's advantageous too.
At some point we're going to change this to `rem` unit, that's why I've
taken distance from changing it to a `px` value for now although devised
differently before.
Bug: T269959
Change-Id: I21cac3f049eed64520dd229ef80d10f9be853e0e