Use variable to set correct path for slick slider

Build/Assets/Scss/base/_variables.scss

@@ -783,3 +783,5 @@ $navbar-brand-padding-y: 0;
 //
 // $pre-color:                         $gray-900 !default;
 // $pre-scrollable-max-height:         340px !default;
+
+$slick-loader-path: "/typo3conf/ext/Resources/Public/Images/ajax-loader.gif"

Build/Assets/Scss/components/_slider.scss

@@ -216,10 +216,6 @@
     }
 }
 
-.slick-loading .slick-list {
-    background: #fff url('../Images/ajax-loader.gif') center center no-repeat;
-}
-
 @include media-breakpoint-down(sm) {
     .landing-slider-wrapper {
         .landing-slick-slider {