ci: move torch-tensorrt to GPU-only test requirements (#21575)
* ci: move torch-tensorrt dependency to GPU-only requirements
torch-tensorrt is GPU-only (requires CUDA) and all its tests use
`@RunIf(min_cuda_gpus=1)`, so installing it in CPU CI provides no
value while blocking PyTorch version upgrades due to wheel
compatibility lag.
* ci: add GPU-specific test requirements to setup