Remove unnecessary style since it will be applied twice

Author: mmehmetAliIzci

styles/web/css/main.css

@@ -50,7 +50,3 @@ div.widget-slider-danger .rc-slider-track {
 div.widget-slider-inverse .rc-slider-track {
     background-color: $brand-inverse;
 }
-
-.rc-slider-tooltip {
-    z-index: 999;
-}