Fix incorrect PPM-PPR match in CommuteCliffordPastPPM

[sengthai]

Context:
Fixed a bug in the verification logic of CommuteCliffordPastPPM and updated the docstring.

Previously, in cases like:

func.func @circuit(%q0: !quantum.bit, %q1: !quantum.bit) {
  %0:2 = qec.ppr ["Z", "X"](4) %q0, %q1 : !quantum.bit, !quantum.bit
  %1 = qec.ppr ["X"](-4) %0#1 : !quantum.bit
  %m1, %2:2 = qec.ppm ["Z", "Z"] %0#0, %1 : !quantum.bit, !quantum.bit
  return
}

The ppm was incorrectly matched with the first ppr, even though %0:2 dominates %1 and %1 dominates %2:2.

Description of the Change:

• Updated verifyNextNonClifford and verifyPrevNonClifford functions to streamline user operation checks.
• Removed redundant checks
• Minor formatting adjustment in ppr_to_ppm function docstring

Benefits:

• Corrects a false matching bug
• Improve docstring

[github-actions]

Hello. You may have forgotten to update the changelog!
Please edit doc/releases/changelog-dev.md on your branch with:

• A one-to-two sentence description of the change. You may include a small working example for new features.
• A link back to this PR.
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[dime10]

Thanks!