[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>

searx/templates/simple/new_issue.html

@@ -54,10 +54,6 @@ or manually by executing the searx/webapp.py file? -->
 {{'  '}}* Function: `{{ error.function }}`
 {{'  '}}* Code: `{{ error.code }}`
 {{'\n'-}}
-{%- endfor -%}
-{%- for test_name, results in engine_reliability.checker.items() -%}
-{%- if loop.first %}Checker{% endif -%}
-{{-'\n  '}}* {{ test_name }}: {% for result in results%}`{{ result }}`,{% endfor -%}
 {%- endfor -%}
     </textarea>
     <input type="checkbox" id="step1">