[BUG] yarn.lock is incorrectly .gitignored, potentially leading to build failures

[saevarb]

Describe the bug
Currently, yarn.lock is gitignore, which it shouldn't. In my fork, which I originally made a few months ago, a lockfile was created automatically. Updating the fork to match the new main branch means my lockfile is now incorrect, which (in my particular scenario) leads to build failures in OpenAIAssistant.ts because the openai version is not correct. This is just one example of a problem that can happen when no lockfile is present.

Expected behavior
The lockfile should be includede as part of the repository.

[HenryHengZJ]

when we switch to pnpm, a frozen lockfile will be provided - #1272