Revert "Safety check: include "Check now" button in Settings search"

This reverts commit 1708a344.

Reason for revert: I forgot that there was an explicit reason why we did exclude the "Check now" button and the safety check parent element secondary label from Settings search: it breaks another user journey:

1. In the main page, the users searches for "Check now" (or for any other string that is matched only by the button or the parent element secondary label). Safety check is shown as a the only result of the Settings search in the main page.
2. The user runs a safety check. The "Check now" button is replaced by the re-run icon button, and the string of the secondary label changes.
3. The user navigates from the main page to another Settings page through safety check to inspect some details.
4. The user navigates back from the Settings page to the main page. Safety check is no longer shown and the main page is empty, as the search term does no longer match anything inside safety check.

Original change's description:
> Safety check: include "Check now" button in Settings search
>
> * Include the previously excluded "Check now" button in the Settings
>   search. This lists safety check as a result when searching for "Check
>   now" if the button is visible at the moment the search is done.
>
> Bug: 1015841,1114020
> Change-Id: I09ba5e15b27371cf6a4aff2105a7bc8f4a33d706
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2339996
> Reviewed-by: dpapad <dpapad@chromium.org>
> Commit-Queue: Rainhard Findling <rainhard@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#795996}

TBR=dpapad@chromium.org,rainhard@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 1015841
Bug: 1114020
Change-Id: Id824aca8bc74b52872e3986cc8b0cb5084183bcf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2362936Reviewed-by: dpapad <dpapad@chromium.org>
Reviewed-by: Rainhard Findling <rainhard@chromium.org>
Commit-Queue: Rainhard Findling <rainhard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#800080}

chrome/browser/resources/settings/safety_check_page/safety_check_page.html

@@ -20,7 +20,7 @@
           restamp>
         <div class="separator"></div>
         <cr-button id="safetyCheckParentButton" class="action-button"
-            on-click="onRunSafetyCheckClick_"
+            on-click="onRunSafetyCheckClick_" no-search
             aria-label="$i18n{safetyCheckParentButtonAriaLabel}">
           $i18n{safetyCheckParentButton}
         </cr-button>