chore(tutorials): drop the unrelated uv.lock version bump

The lock change only rewrote the SDK's own recorded version
(0.21.0 to 0.28.2), a side effect of a local uv run. The polling change
doesn't need it, and leaving it in risks a conflict with the next
release or reconcile commit that touches uv.lock.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: danielmillerp