Adds the white color back to the alret banners

app/assets/stylesheets/bootstrap_migration.scss

@@ -160,6 +160,11 @@ table {
   }
 }
 
+.alert-warning,
+.alert-warning .alert-link {
+  color: $white-light;
+}
+
 // Polyfill deprecated selectors
 
 .hidden {
@@ -271,4 +276,4 @@ pre code {
 
 input[type=color].form-control {
   height: $input-height;
-}
+}
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