Fix frontend miscounting AI requests when using Chrome AI

[mwatson]

Currently the front-end counts requests to Chrome AI against a user's total AI requests. The counts are not reflected on the backend, so this is just an issue with the frontend. There's likely an event that triggers the counter (probably the done event) and we just need to not increment the counter when it's sent by the Chrome AI code.

[github-actions]

OpenAI suggested the following labels for this issue:

• [Feature Group] Other Infrastructure: The issue relates to frontend functionality and how it connects with backend processes, which falls under infrastructure improvements.
• [Feature] AI: The issue directly pertains to requests related to the Chrome AI integration, which falls under AI tools.
• [Feature] Performance History: The counting misrepresentation could impact performance metrics tracked by the frontend related to AI requests.