Bug 1567335 - Make sure the animation class for the foreground element is removed. r=gl

Differential Revision: https://phabricator.services.mozilla.com/D38805

--HG--
extra : moz-landing-system : lando

devtools/client/inspector/markup/utils.js

@@ -66,6 +66,8 @@ function flashElementOff(
   backgroundElt.classList.remove(backgroundClass);
 
   foregroundElt.classList.remove("theme-fg-contrast");
+  // Make sure the foreground animation class is removed
+  foregroundElt.classList.remove("flash-out");
   [].forEach.call(
     foregroundElt.querySelectorAll("[class*=theme-fg-color]"),
     span => span.classList.remove("theme-fg-contrast")