objstorage_checker: Use check method from object storage interface

Instead of reinventing the wheel, prefer to use the check method from the object storage interface for verifying content presence and integrity.

Depends on !65 (merged) and swh-objstorage!178 (merged).

Related to #4694 (closed).

swh/scrubber/interface.py

-# Copyright (C) 2024  The Software Heritage developers
-# See the AUTHORS file at the top-level directory of this distribution
-# License: GNU General Public License version 3, or any later version
-# See top-level LICENSE file for more information
-
-
-from typing_extensions import Protocol, runtime_checkable
-
-from swh.core.statsd import Statsd
-
-from .db import ConfigEntry, Datastore
-
-
-@runtime_checkable
-class CheckerInterface(Protocol):
-    @property
-    def config(self) -> ConfigEntry:
-        ...
-
-    @property
-    def datastore(self) -> Datastore:
-        ...
-
-    @property
-    def statsd(self) -> Statsd:
-        ...
-
-    def run(self) -> None:
-        ...