Fix colorPicker tests (#11312)

* Fix colorPicker tests

In IE11, the click-layer needs longer time to load.

uitest/src/test/java/com/vaadin/tests/components/colorpicker/ColorPickerUserColorChangeTest.java

@@ -14,7 +14,7 @@ public class ColorPickerUserColorChangeTest extends MultiBrowserTest {
         openTestURL();
         // Open colorPicker
         findElement(By.className("v-button-v-colorpicker ")).click();
-        sleep(100);
+        sleep(500);
         // click somewhere inside the gradient layer
         findElement(By.className("v-colorpicker-gradient-clicklayer")).click();
         // confirm selection by clicking "OK" button