subresource_filter: Remove tripping DCHECK

This DCHECK is (rarely) seen in the wild (in DCHECK-enabled) builds,
likely caused by https://crbug.com/1234233. Given this isn't actively
being worked on, and the result is that we'll simply overwrite the
existing ThrottleManager, removing this DCHECK to avoid reports.

Bug: 1264667
Change-Id: I6b5e40bf5d12dd0fc05712ede01d49763d8a5363
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5026197
Reviewed-by: Alex Turner <alexmt@chromium.org>
Commit-Queue: David Bokan <bokan@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1225586}

components/subresource_filter/content/browser/content_subresource_filter_web_contents_helper.cc

@@ -302,7 +302,7 @@ void ContentSubresourceFilterWebContentsHelper::DidFinishNavigation(
         // https://groups.google.com/a/chromium.org/g/navigation-dev/c/cY5V-w-xPRM/m/uC1Nsg_KAwAJ.
         // DCHECK(rfh->GetLastCommittedURL().is_empty() ||
         //        rfh->GetLastCommittedURL().IsAboutBlank());
-        DCHECK(!GetThrottleManager(rfh->GetPage()));
+        // DCHECK(!GetThrottleManager(rfh->GetPage()));
         page = &rfh->GetPage();
       }
     }