docs(samples): add LRO code snippets (#209)

* docs(samples): add LRO code snippets

* lint fix

* lint fix

* lint fix

* 🦉 Updates from OwlBot

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: galz10

packages/google-cloud-dialogflow-cx/README.md

@@ -148,6 +148,7 @@ Samples are in the [`samples/`](https://github.com/googleapis/nodejs-dialogflow-
 | List-page | [source code](https://github.com/googleapis/nodejs-dialogflow-cx/blob/main/samples/list-page.js) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-dialogflow-cx&page=editor&open_in_editor=samples/list-page.js,samples/README.md) |
 | List-testcase-results | [source code](https://github.com/googleapis/nodejs-dialogflow-cx/blob/main/samples/list-testcase-results.js) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-dialogflow-cx&page=editor&open_in_editor=samples/list-testcase-results.js,samples/README.md) |
 | List Training Phrases | [source code](https://github.com/googleapis/nodejs-dialogflow-cx/blob/main/samples/listTrainingPhrases.js) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-dialogflow-cx&page=editor&open_in_editor=samples/listTrainingPhrases.js,samples/README.md) |
+| Long-running-operation | [source code](https://github.com/googleapis/nodejs-dialogflow-cx/blob/main/samples/long-running-operation.js) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-dialogflow-cx&page=editor&open_in_editor=samples/long-running-operation.js,samples/README.md) |
 | Quickstart | [source code](https://github.com/googleapis/nodejs-dialogflow-cx/blob/main/samples/quickstart.js) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-dialogflow-cx&page=editor&open_in_editor=samples/quickstart.js,samples/README.md) |
 | Update-intent | [source code](https://github.com/googleapis/nodejs-dialogflow-cx/blob/main/samples/update-intent.js) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-dialogflow-cx&page=editor&open_in_editor=samples/update-intent.js,samples/README.md) |
 | Webhooks | [source code](https://github.com/googleapis/nodejs-dialogflow-cx/blob/main/samples/webhooks.js) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-dialogflow-cx&page=editor&open_in_editor=samples/webhooks.js,samples/README.md) |

packages/google-cloud-dialogflow-cx/protos/protos.d.ts

@@ -22,6 +22,7 @@
   * [List-page](#list-page)
   * [List-testcase-results](#list-testcase-results)
   * [List Training Phrases](#list-training-phrases)
+  * [Long-running-operation](#long-running-operation)
   * [Quickstart](#quickstart)
   * [Update-intent](#update-intent)
   * [Webhooks](#webhooks)
@@ -211,6 +212,23 @@ __Usage:__
 
 
 
+### Long-running-operation
+
+View the [source code](https://github.com/googleapis/nodejs-dialogflow-cx/blob/main/samples/long-running-operation.js).
+
+[![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-dialogflow-cx&page=editor&open_in_editor=samples/long-running-operation.js,samples/README.md)
+
+__Usage:__
+
+
+`node samples/long-running-operation.js`
+
+
+-----
+
+
+
+
 ### Quickstart
 
 View the [source code](https://github.com/googleapis/nodejs-dialogflow-cx/blob/main/samples/quickstart.js).