[Internal] Fix a couple of typos in open_ai_client.py (#829)

## What changes are proposed in this pull request?

This PR fixes a couple of typos in `open_ai_client.py`.

## How is this tested?

N/A

databricks/sdk/mixins/open_ai_client.py

@@ -29,7 +29,7 @@ def get_open_ai_client(self):
             from openai import OpenAI
         except Exception:
             raise ImportError(
-                "Open AI is not installed. Please install the Databricks SDK with the following command `pip isntall databricks-sdk[openai]`"
+                "Open AI is not installed. Please install the Databricks SDK with the following command `pip install databricks-sdk[openai]`"
             )
 
         return OpenAI(
@@ -42,7 +42,7 @@ def get_langchain_chat_open_ai_client(self, model):
             from langchain_openai import ChatOpenAI
         except Exception:
             raise ImportError(
-                "Langchain Open AI is not installed. Please install the Databricks SDK with the following command `pip isntall databricks-sdk[openai]` and ensure you are using python>3.7"
+                "Langchain Open AI is not installed. Please install the Databricks SDK with the following command `pip install databricks-sdk[openai]` and ensure you are using python>3.7"
             )
 
         return ChatOpenAI(