[breaking] Bump Python requirement to 3.10. (#10434)

- Bump the Python requirement.
- Fix type hints.
- Use loky to avoid deadlock.
- Workaround cupy-numpy compatibility issue on Windows caused by the `safe` casting rule.
- Simplify the repartitioning logic to avoid dask errors.

demo/aft_survival/aft_survival_viz_demo.py

@@ -106,8 +106,8 @@ plt.figure(figsize=(12, 13))
 bst = xgb.train(
     params,
     dmat,
-    15,
-    [(dmat, "train")],
+    num_boost_round=15,
+    evals=[(dmat, "train")],
     evals_result=res,
     callbacks=[PlotIntermediateModel()],
 )