fix (preset values): remove placehoder when mark mode (#3515)

Author: Arukuen

src/components/advanced-range-control/index.js

@@ -184,6 +184,7 @@ const AdvancedRangeControl = props => {
 		// Other necessary props for steps.
 		propsToPass.withInputField = false
 		controlProps.units = false
+		propsToPass.placeholder = ''
 	} else {
 		propsToPass.marks = undefined
 	}

src/components/advanced-range-control/range-control.js

@@ -144,11 +144,6 @@ const StackableRangeControl = memo( props => {
 		placeholderValue = initialPosition
 	}
 
-	// Remove placeholder if it's a custom CSS
-	if ( typeof placeholderValue === 'string' && placeholderValue.startsWith( 'var' ) ) {
-		placeholderValue = ''
-	}
-
 	return <div
 		className={ classNames }
 		style={ { '--ugb-advanced-range-control--width': percentageValue } }

src/components/four-range-control/index.js

@@ -355,6 +355,7 @@ const FourRangeControl = memo( props => {
 
 			// Other necessary props for steps.
 			newProps.withInputField = false
+			propsToPass.placeholder = ''
 		} else {
 			newProps.marks = undefined
 		}