HUE-8297 [frontend] Remove gray background on hover in the nav bars

desktop/core/src/desktop/static/desktop/less/hue-cui-overrides.less

@@ -40,7 +40,7 @@
   }
 
   ul.nav li a:hover, ul.nav li a:focus  {
-    background-color: @cui-purple-gray-050;
+    background-color: inherit;
   }
 }