opt: reduce estimated messages

[simlecode]

关联的Issues (Related Issues)

close

改动 (Proposed Changes)

调整预估消息的数量和选择消息的数量一致

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.
• 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

Merging #373 (e5928d0) into master (e2bd8fd) will decrease coverage by 0.03%.
The diff coverage is 100.00%.

❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #373      +/-   ##
==========================================
- Coverage   58.10%   58.07%   -0.03%     
==========================================
  Files          68       68              
  Lines        7616     7616              
==========================================
- Hits         4425     4423       -2     
- Misses       2835     2836       +1     
- Partials      356      357       +1     

Flag	Coverage Δ
unittests	58.07% <100.00%> (-0.03%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
service/message_selector.go	76.76% <100.00%> (-0.41%)	⬇️

[LinZexiao]

LGTM