chore: remove accidentally-introduced top-level yarn.lock

The root yarn.lock (86-byte empty file) was unintentionally committed
in #22759 (kv-store sqlite backend) on v4-next. It was already removed
on next via #22987, but that removal hasn't propagated to v4-next yet.
Removing directly here so the v4 branch doesn't inherit the stray file.

Addresses @alexghr's review comment on #23306.

Author: aminsammara