fixup! BB 32308: Use direct browser sizing for letterboxing.

When the dimension is less than 50px, we need to return dimension
itself, rather than a 0px margin.

toolkit/components/resistfingerprinting/RFPHelper.sys.mjs

@@ -525,7 +525,7 @@ class _RFPHelper {
   steppedSize(aDimension, aIsWidth = false) {
     let stepping;
     if (aDimension <= 50) {
-      return 0;
+      return aDimension;
     } else if (aDimension <= 500) {
       stepping = 50;
     } else if (aDimension <= 1600) {