Fix flutter scroll issue

Author: subramanya

src/main/java/io/appium/java_client/flutter/commands/ScrollParameter.java

@@ -18,7 +18,7 @@
 @Setter
 public class ScrollParameter extends FlutterCommandParameter {
     private AppiumBy.FlutterBy scrollTo;
-    private WebElement scrollView;
+    private AppiumBy.FlutterBy scrollView;
     private ScrollDirection scrollDirection;
     private Integer delta;
     private Integer maxScrolls;
@@ -56,13 +56,13 @@ public Map<String, Object> toJson() {
 
         params.put("finder", parseFlutterLocator(scrollTo));
         Optional.ofNullable(scrollView)
-                .ifPresent(scrollView -> params.put("scrollView", scrollView));
+                .ifPresent(scrollView -> params.put("scrollView", parseFlutterLocator(scrollView)));
         Optional.ofNullable(delta)
                 .ifPresent(delta -> params.put("delta", delta));
         Optional.ofNullable(maxScrolls)
-                .ifPresent(maxScrolls -> params.put("delta", maxScrolls));
+                .ifPresent(maxScrolls -> params.put("maxScrolls", maxScrolls));
         Optional.ofNullable(settleBetweenScrollsTimeout)
-                .ifPresent(timeout -> params.put("delta", settleBetweenScrollsTimeout));
+                .ifPresent(timeout -> params.put("settleBetweenScrollsTimeout", settleBetweenScrollsTimeout));
         Optional.ofNullable(scrollDirection)
                 .ifPresent(direction -> params.put("scrollDirection", direction.getDirection()));
         Optional.ofNullable(dragDuration)