[BUG] Breaking on Opus without proper error reporting on UI level

## Describe the bug

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The Claude 3 (Opus) model is currently unavailable due to a throughput limitation. The system is unable to process the request at this time.

Request:
It would be helpful if the actual error message ("The provided model doesn't support on-demand throughput") was displayed directly in the user interface, rather than the generic "An error occurred while responding." This would provide users with more specific information about the issue without requiring them to use web inspection tools for debugging.

## To Reproduce

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Steps to reproduce the behavior:

1. Go to Home screen
2. Open WebInseptor
3. open network tab
4. select WebScoket filter
5. focus back on the main screen
6. Click on "Claude 3 (Opus)" (select)
7. Type "Hi" and press enter
8. See error: "An error occurred while responding."
9. check the WebSocket message flow in inspector
10. find last mesage "Failed to run stream handler: An error occurred (ValidationException) when calling the ConverseStream operation: The provided model doesn't support on-demand throughput."

## Screenshots

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## Additional context

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