[Whisper] Decompose cross-attention SDPA for NPU too, matching CPU/GPU - #4306

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: akladiev/labeler@eeac5941e7fb6f980d47e038ac0665168851c874. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/