FIX: Correct position of topic progress in iOS when composer is visible

This fix is needed due to what feels like an iOS Safari bug. The CSS rule `margin-bottom: env(safe-area-inset-bottom);` should not apply to the topic progress element when the composer is visible, because the element is not near the bottom of the viewport.

app/assets/javascripts/discourse/components/topic-progress.js.es6

@@ -185,6 +185,10 @@ export default Ember.Component.extend({
     } else {
       $wrapper.css(wrapperDir, "1em");
     }
+
+    if (!isDocked) {
+      $wrapper.css("margin-bottom", "0px");
+    }
   },
 
   click(e) {