Use 19px not 16px type in more places

Making the navigation narrower means that we have more space on every
page. So on pages where we had to use 16px type just to fit stuff on the
page we can now bump the type size up to something less miserly. This is
mainly the team and settings pages.

We still need to use 16px on pages which list notifications or previews
of spreadsheets, because we’re still trying to fit a lot of information
onto these pages, so every little space-saving helps.

app/assets/stylesheets/components/tick-cross.scss

@@ -1,6 +1,6 @@
 %tick-cross {
 
-  @include core-16;
+  @include core-19;
   display: inline-block;
   background-size: 19px 19px;
   background-repeat: no-repeat;