include XGBoost CUDA packages in CUDA 13 images

[jameslamb]

Closes #784

In #782, we skipped cuML notebook testing on CUDA 13 because there weren't yet CUDA 13 xgboost conda packages. Those exist now:

• Add CUDA 13 builds xgboost-feedstock#100
• restore rapids-xgboost dependency, update to xgboost 3.0.5, update pre-commit hooks integration#800

This reverts a workaround from #782, so all notebooks will be tested on CUDA 12 and CUDA 13. It also ensures that the CUDA 13 images include GPU-accelerated builds of xgboost.

[jameslamb]

/merge