fix: beacon: validate drand change at nv16 correctly

[simlecode]

关联的Issues (Related Issues)

https://github.com/filecoin-project/lotus/pull/11690/files

改动 (Proposed Changes)

附注 (Additional Info)

自查清单 (Checklist)

在你认为本 PR 满足被审阅的标准之前，需要确保 / Before you mark the PR ready for review, please make sure that:

• [ ] 符合Venus项目管理规范中关于PR的相关标准 / The PR follows the PR standards set out in the Venus project management guidelines
• [ ] 具有清晰明确的commit message / All commits have a clear commit message.
• [ ] 包含相关的的测试用例或者不需要新增测试用例 / This PR has tests for new functionality or change in behaviour or not need to add new tests.
• [ ] 存在兼容性问题（接口, 配置，数据，灰度），如果存在需要进行文档说明 / This PR has compatibility issues (API, Configuration, Data, GrayRelease), if so, need to be documented.
• [ ] 包含相关的的指南以及文档或者不需要新增文档 / This PR has updated usage guidelines and documentation or not need
• [ ] 通过必要的检查项 / All checks are green

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 7 lines in your changes are missing coverage. Please review.

Project coverage is 25%. Comparing base (9c713ca) to head (ffcf2d6).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## feat/nv22 #6280 +/- ## ========================================= - Coverage 25% 25% -1% ========================================= Files 649 649 Lines 80884 80861 -23 ========================================= - Hits 20758 20743 -15 + Misses 57413 57406 -7 + Partials 2713 2712 -1 ```