fix: fix v6 block not showing up for cancel example (aws-amplify#6747)

Author: erinleigh90

src/pages/[platform]/build-a-backend/restapi/restapi-v5-to-v6-migration-guide/index.mdx

@@ -460,53 +460,53 @@ For v6 REST APIs, all API's use the same underlying input/output types, although
 The process for cancelling a request has changed in v6. In v5 you send in the promise as input to the API.cancel API. In v6, cancel is a function returned with the result of an API(REST) operation. To cancel an operation, you will call `operation.cancel()`.
 
 <BlockSwitcher>
-  <Block name="V5">
+  <Block name="V6">
     ```js
-    import { API } from 'aws-amplify'
+    import { get, isCancelError } from 'aws-amplify/api'
 
-    const promise = API.get(
-      apiName, 
-      path, 
+    const operation = get({
+      apiName,
+      path,
       options
-    );
+    });
 
-    promise.then(result => {
+    operation.response.then(result => {
       // GET operation completed successfully
     }).catch(error => {
       // If the error is because the request was cancelled you can confirm here.
-      if(API.isCancel(error)) {
+      if(isCancelError(error)) {
         // 'my message for cancellation'
         console.log(error.message);
       }
-    });
+    })
 
     // To cancel the above request
-    API.cancel(promise, 'my message for cancellation');
+    operation.cancel('my message for cancellation');
     ```
 
   </Block>
-  <Block>
+  <Block name="V5">
     ```js
-    import { get, isCancelError } from 'aws-amplify/api'
+    import { API } from 'aws-amplify'
 
-    const operation = get({
-      apiName,
-      path,
+    const promise = API.get(
+      apiName, 
+      path, 
       options
-    });
+    );
 
-    operation.response.then(result => {
+    promise.then(result => {
       // GET operation completed successfully
     }).catch(error => {
       // If the error is because the request was cancelled you can confirm here.
-      if(isCancelError(error)) {
+      if(API.isCancel(error)) {
         // 'my message for cancellation'
         console.log(error.message);
       }
-    })
+    });
 
     // To cancel the above request
-    operation.cancel('my message for cancellation');
+    API.cancel(promise, 'my message for cancellation');
     ```
 
   </Block>