Bug 863418 - [email] v1-train "No mail in this folder" display has tiny text due to bad v1-train uplift. r=asuth, a=blocking-b2g=leo+

This is a manually checked/assisted uplift of:
Bug 845071 - Email Search - No Matches Screen Update
(cherry picked from commit 4b488e8a61d7fe27874fa0e5e05cea7a86cdd058)

The uplift was not previously made because of confusion because of a bad uplift.
Merge pull request #11153 from asutherland/email-search-screen-fix

Bug 863418 - [email] v1-train "No mail in this folder" display has tiny text due to bad v1-train uplift. r=asuth, a=blocking-b2g=leo+