[mod] drop SearXNG's checker (#5767)

To date, there is no analysis for the checker that could be evaluated in any
meaningful way.

- https://github.com/searxng/searxng/issues/3407
- https://github.com/searxng/searxng/pull/3312

The checker would need to be completely redesigned, but even then, its
usefulness and the maintenance required for it would be disproportionate.

TBH: In its current form, it is useless and only consumes resources and
causes the engines to be blocked, because these tests (query terms) come
from *hundreds* of instances and could be interpreted as bot attacks.

Related issues: [search.checker](https://github.com/searxng/searxng/issues?q=label%3A%22search.checker%22)

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

tests/__init__.py

@@ -82,7 +82,6 @@ class SearxTestCase(aiounittest.AsyncTestCase):
         # - initialize searx.network, searx.metrics, searx.processors and searx.search.checker
 
         searx.search.initialize(
-            enable_checker=True,
             check_network=True,
             enable_metrics=searx.get_setting("general.enable_metrics"),  # type: ignore
         )