[vLLM][moe] Route blockwise FP8 fused MoE to Triton

[sarah12121212]

Summary

• For blockwise quantization key pair activation_key == kFp8Dynamic128Sym and weight_key == kFp8Static128BlockSym route fused MoE through Triton instead of the native Xe2 grouped-GEMM path, which accepts only 1D per-expert scales and rejects multidimensional scale grids.

• Unskip the 44 affected Xe2 tests.

Blocked by #7462 (it needs to be merged first)
Relates to issue #7574

Testing

vLLM MoE suite on B580 (tested locally):

2,987 tests
794 passed
2,193 skipped
0 failures

vLLM MoE suite on PVC max 1100: