Update model deployment in intent_mapping.prompty to match .env configuration

### Operating System

Windows

### Version Information

NA

### Steps to reproduce

In the azureai-samples/scenarios/rag/custom-rag-app/assets/intent_mapping.prompty file, the model deployment is currently set to **gpt-4o**:

configuration:
azure_deployment: gpt-4o

However, in the lab setup, the **.env** file specifies gpt-4o-mini as the intended model for inference:

EVALUATION_MODEL="gpt-4o-mini"
INTENT_MAPPING_MODEL="gpt-4o-mini"

While the application still functions as expected due to the correct model being provided via environment variables, this discrepancy between the prompt template and the .env file may cause confusion and misalignment, especially for users reviewing or modifying the configuration.

Suggestion:

Please update the azure_deployment field in intent_mapping.prompty file to **gpt-4o-mini**

azure_deployment: gpt-4o-mini

This will ensure consistency between the prompt template and the runtime configuration.

### Expected behavior

NA

### Actual behavior

NA

### Addition information

_No response_