[Misc][Core] Remove unused req_index increment in scheduler

[ivanium]

Purpose

Clean up the v1 scheduler by removing an unused req_index += 1 increment that remained after refactoring the waiting-queue scheduling logic.
This line no longer affects control flow (the index is not used in this loop) and could be confusing.

Test Plan

• Run existing scheduler unit tests to confirm no behavior changes.
  • e.g. pytest tests/v1/core -q (or a narrower subset that exercises Scheduler scheduling paths)

Test Result

Succeeded.

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[gemini-code-assist]

Code Review

This pull request removes an unused increment of the req_index variable within the schedule method of the Scheduler class. The variable was used for iterating over running requests in a previous loop but was also being incremented in the subsequent loop for waiting requests, where it has no effect. This change is a good cleanup that improves code clarity by removing dead code. The change is correct and I approve it.