RTL: Fixed screen-reader-only elements pushout out view

For #4429

Author: ssddanbrown

resources/sass/_layout.scss

@@ -304,7 +304,7 @@ body.flexbox {
 
 .screen-reader-only {
   position: absolute;
-  left: -10000px;
+  inset-inline-start: -10000px;
   top: auto;
   width: 1px;
   height: 1px;