Fix crash on Input Tester example with certain input events

If an Input event with inputType  "insertReplacementText" is received, the example crashes because "event.dataTransfer.get is not a function"
The correct API is `getData()`, not `get()`.
Ref: https://developer.mozilla.org/en-US/docs/Web/API/DataTransfer/getData

examples/input-tester/index.js

@@ -176,7 +176,7 @@ const Event = ({ event, targetRange, selection }) => {
       </td>
       <td>
         <StringCell
-          value={event.dataTransfer && event.dataTransfer.get('text/plain')}
+          value={event.dataTransfer && event.dataTransfer.getData('text/plain')}
         />
       </td>
       <td>