[Bug] wrong result of searchOffset in tiered storage

[yuz10]

Before Creating the Bug Report

• I found a bug, not just asking a question, which should be created in GitHub Discussions.

• I have searched the GitHub Issues and GitHub Discussions of this repository and believe that this is not a duplicate.

• I have confirmed that this bug belongs to the current repository, not other repositories of RocketMQ.

Runtime platform environment

Ubuntu

RocketMQ version

5.1.0

JDK Version

1.8.0

Describe the Bug

There are 3 segments in fileSegmentList, TieredFlatFile.getFileByTime(timestamp=0, boundaryType=LOWER) should return the first segment, but now returns the last segment.

Steps to Reproduce

1. start broker with tiered storage
2. send some messages.
3. use consumer.searchOffset to search offset with parameter timestamp=0, boundaryType=LOWER

What Did You Expect to See?

searchOffset should return min offset.

What Did You See Instead?

searchOffset not returns min offset.

Additional Context

No response