optimized qmoe code path for 1 token (#27383)
avoids gpu -> cpu copy in qmoe and removes 1 of 6 shaders in qmoe.
This improves token generation on gpt-oss-20b by ~15%
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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Author
Guenther Schmuelling