Added missing role assignments for AI Studio Project

Added the 'Reader' role permission that is required to utilize AI Studio chat playground to load search indexes created by AI Search.

Author: troyhite

articles/ai-services/openai/how-to/use-your-data-securely.md

@@ -273,6 +273,7 @@ So far you have already setup each resource work independently. Next you need to
 | `Storage Blob Data Contributor` | Azure OpenAI | Storage Account | Reads from the input container, and writes the preprocessed result to the output container. |
 | `Cognitive Services OpenAI Contributor` | Azure AI Search | Azure OpenAI | Custom skill. |
 | `Storage Blob Data Reader` | Azure AI Search | Storage Account | Reads document blobs and chunk blobs. |
+| `Reader` | Azure AI Studio Project | Azure Storage Private Endpoints (Blob & File) | Read search indexes created in blob storage within an AI Studio Project. |
 | `Cognitive Services OpenAI User` | Web app | Azure OpenAI | Inference. |