Catch exception that is thrown when Grid is scrolled during operation

IllegalStateException may occur if user has scrolled Grid so that Escalator has updated, and row under Editor is no longer there
Fixes https://github.com/vaadin/framework/issues/11463

client/src/main/java/com/vaadin/client/widgets/Grid.java

@@ -2140,15 +2140,21 @@ public class Grid<T> extends ResizeComposite implements HasSelectionHandlers<T>,
             double newLeft = frozenWidth - scrollLeft;
             cellWrapper.getStyle().setLeft(newLeft, Unit.PX);
 
-            // sometimes focus handling twists the editor row out of alignment
-            // with the grid itself and the position needs to be compensated for
-            TableRowElement rowElement = grid.getEscalator().getBody()
+            try {
+                // sometimes focus handling twists the editor row out of alignment
+                // with the grid itself and the position needs to be compensated for
+                TableRowElement rowElement = grid.getEscalator().getBody()
                     .getRowElement(grid.getEditor().getRow());
-            int rowLeft = rowElement.getAbsoluteLeft();
-            int editorLeft = cellWrapper.getAbsoluteLeft();
-            if (editorLeft != rowLeft + frozenWidth) {
-                cellWrapper.getStyle().setLeft(newLeft + rowLeft - editorLeft,
+                int rowLeft = rowElement.getAbsoluteLeft();
+                int editorLeft = cellWrapper.getAbsoluteLeft();
+                if (editorLeft != rowLeft + frozenWidth) {
+                    cellWrapper.getStyle().setLeft(newLeft + rowLeft - editorLeft,
                         Unit.PX);
+                }
+            } catch (IllegalStateException e) {
+                // IllegalStateException may occur if user has scrolled Grid so
+                // that Escalator has updated, and row under Editor is no longer
+                // there
             }
         }