Fix [3462] Incorrect method of reading indicator files

[manojks1999]

Describe what this PR does / why we need it

Fixes for #3462

Does this pull request fix one issue?

Fixes #3462

Describe how you did it

Removed line 209 of sentinel-core/src/main/java/com/alibaba/csp/sentinel/node/metric/MetricSearcher.java

Describe how to verify it

Special notes for reviews

[CLAassistant]

All committers have signed the CLA.

[LearningGp]

This code is currently processing an index file. I'm having trouble mapping the issue description to the observed behavior - could you please elaborate on the exact conditions/reproduction steps you're encountering? Additionally, if we remove this line, the while condition would incorrectly compare Index with beginSecond, which is semantically invalid as these represent different dimensional units in our processing pipeline.