fix(slider): remove duplicate property declarations

Author: cdransf

components/slider/index.css

@@ -83,9 +83,6 @@
 	--spectrum-slider-label-text-color-disabled: var(--spectrum-disabled-content-color);
 	--spectrum-slider-tick-mark-color-disabled: var(--spectrum-disabled-background-color);
 	--spectrum-slider-ramp-handle-border-color-active: var(--spectrum-gray-100);
-	--spectrum-slider-handle-background-color: transparent;
-	--spectrum-slider-handle-background-color-disabled: transparent;
-	--spectrum-slider-ramp-handle-background-color: var(--spectrum-gray-75);
 
 	/* values */
 	--spectrum-slider-input-left: calc(var(--spectrum-slider-handle-margin-left) / 4);