fix: show error after Cody response in chat UI

[abeatrix]

This PR addresses the issue mentioned in #2539, where long response from chat gpt 4.0 will resulted in error, and the error message will replace the response text from Cody.

• Display error message in additional to the text that cody has already responded
• Add new styles for .request-error and .request-error-title classes.
• Update ErrorItem.tsx to use new CSS classes for request error display.

Test plan

1. Switch chat to use chat gpt 4.0
2. Open a large file and select the whole file
3. Run the /test command
4. If the response is longer than the answer limit, it should display an error message after the text that Cody has already responsed

• before: the text will be replaced with the error message

Demo

Before

Screen.Recording.2024-01-04.at.9.59.38.AM.mov

https://www.loom.com/share/2136a5de267d4c21849b735bb38619d9?sid=b8d8652e-2bba-4498-bcf6-aec9c2c9a0cc

After

Error message will not replace the text that's already returned by the LLM

https://www.loom.com/share/3e183dfec7f940079100b48e519235eb?sid=2e55abad-e4d4-4ba0-8a6a-05078f48ef0a

[chwarwick]

This makes sense to me