Inconsistency with using namespaces with `__brick_.*` calls in algorithm_impl.h

[dmitriy-sobolev]

There are a lot of other places in this file, when we use __brick_.* functions without namespaces, which is inconsistent.

Originally posted by @dsobolev-dev in https://github.com/oneapi-src/oneDPL/pull/395#discussion_r737259476