chore: bump @across-protocol/sdk to 4.3.161

[droplet-rl]

Summary

• Bumps @across-protocol/sdk from 4.3.160 to 4.3.161.
• The new version contains across-protocol/sdk#1443, which preserves the underlying SolanaError type through QuorumFallbackSolanaRpcFactory. Previously the factory wrapped slot-skipped errors in a generic Error, defeating _callGetTimestampForSlotWithRetry's isSolanaError(err) guard and causing getNearestSlotTime to throw instead of walking back to the prior valid slot.
• Live symptom (Slack-triaged): zion-across-l2-executor-solana (dataworker) crashed with Not enough providers succeeded on getBlockTime call whenever the chain head briefly landed in a Solana skipped-slot range. Slot 421829272 was the trigger — reproducible against the public mainnet RPC at the time.

Test plan

• yarn install --ignore-scripts syncs yarn.lock cleanly; only package.json + yarn.lock change.
• yarn why @across-protocol/sdk reports 4.3.161 as the resolved version with no other consumers pinning an older copy.
• CI green on this branch before merge.
• After deploy, confirm zion-across-l2-executor-solana no longer trips on the same getBlockTime stack.

🤖 Generated with Claude Code

[droplet-rl]

Checked the review (pullrequestreview-4353331009) — pxrl's submission is a clean APPROVED with an empty body and zero inline comments. Confirmed via the GitHub API:

• GET /pulls/3415/reviews → one review, state: "APPROVED", body: "".
• GET /pulls/3415/comments → empty (no inline review comments).
• GET /issues/3415/comments → empty (no thread comments).

No feedback to address, so no code changes pushed. PR is mergeable (mergeable_state: "clean") once CI finishes. Remaining gating items are the two unchecked boxes from the PR description — CI green and post-deploy verification on zion-across-l2-executor-solana.