Update chat-with-pdf-azure.ipynb (Typo "Azure Open AI"→"Azure OpenAI") (#3351)

# Description
Please add an informative description that covers that changes made by
the pull request and link all relevant issues.
* Typo "Azure Open AI"→"Azure OpenAI"
*
https://github.com/microsoft/promptflow/blob/main/examples/flows/chat/chat-with-pdf/chat-with-pdf-azure.ipynb
* #PingMSFTDocs

# All Promptflow Contribution checklist:
- [ ] **The pull request does not introduce [breaking changes].**
- [ ] **CHANGELOG is updated for new features, bug fixes or other
significant changes.**
- [ ] **I have read the [contribution guidelines](../CONTRIBUTING.md).**
- [ ] **Create an issue and link to the pull request to get dedicated
review from promptflow team. Learn more: [suggested
workflow](../CONTRIBUTING.md#suggested-workflow).**

## General Guidelines and Best Practices
- [ ] Title of the pull request is clear and informative.
- [ ] There are a small number of commits, each of which have an
informative message. This means that previously merged commits do not
appear in the history of the PR. For more information on cleaning up the
commits in your PR, [see this
page](https://github.com/Azure/azure-powershell/blob/master/documentation/development-docs/cleaning-up-commits.md).

### Testing Guidelines
- [ ] Pull request includes test coverage for the included changes.

Co-authored-by: Clement Wang <47586720+wangchao1230@users.noreply.github.com>

Author: hyoshioka0128

examples/flows/chat/chat-with-pdf/chat-with-pdf-azure.ipynb

@@ -80,7 +80,7 @@
     "\n",
     "Connection in prompt flow is for managing settings of your application behaviors incl. how to talk to different services (Azure OpenAI for example).\n",
     "\n",
-    "Prepare your Azure Open AI resource follow this [instruction](https://learn.microsoft.com/en-us/azure/cognitive-services/openai/how-to/create-resource?pivots=web-portal) and get your `api_key` if you don't have one.\n",
+    "Prepare your Azure OpenAI resource follow this [instruction](https://learn.microsoft.com/en-us/azure/cognitive-services/openai/how-to/create-resource?pivots=web-portal) and get your `api_key` if you don't have one.\n",
     "\n",
     "Please go to [workspace portal](https://ml.azure.com/), click `Prompt flow` -> `Connections` -> `Create`, then follow the instruction to create your own connections. \n",
     "Learn more on [connections](https://learn.microsoft.com/en-us/azure/machine-learning/prompt-flow/concept-connections?view=azureml-api-2)."