[coll] Pass context to various functions. (#9772)

* [coll] Pass context to various functions.

In the future, the `Context` object would be required for collective operations, this PR
passes the context object to some required functions to prepare for swapping out the
implementation.

src/metric/survival_metric.cu

@@ -217,7 +217,7 @@ struct EvalEWiseSurvivalBase : public MetricNoCache {
     return Policy::GetFinal(dat[0], dat[1]);
   }
 
-  const char* Name() const override {
+  [[nodiscard]] const char* Name() const override {
     return policy_.Name();
   }