fix: update the max tokens configuration for Azure GPT-4o (2024-08-06) to 16384

[fengjiajie]

Summary

According to the description at this link, the output token limit for GPT-4o (2024-08-06) is 16,384. It's possible that the code is still using the earlier version's (2024-05-13) value of 4,096.

Screenshots

Checklist

Important

Please review the checklist below before submitting your pull request.

• This change requires a documentation update, included: Dify Document
• I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.
• I ran dev/reformat(backend) and cd web && npx lint-staged(frontend) to appease the lint gods