fix: remove CHECK_EQ for swapped RFH (#30820)

|old_host| may be nullptr if the previous RFH was shutdown.

shell/browser/api/electron_api_web_contents.cc

@@ -1421,12 +1421,11 @@ void WebContents::RenderFrameHostChanged(content::RenderFrameHost* old_host,
   // If an instance of WebFrameMain exists, it will need to have its RFH
   // swapped as well.
   //
-  // |old_host| can be a nullptr in so we use |new_host| for looking up the
+  // |old_host| can be a nullptr so we use |new_host| for looking up the
   // WebFrameMain instance.
   auto* web_frame =
       WebFrameMain::FromFrameTreeNodeId(new_host->GetFrameTreeNodeId());
   if (web_frame) {
-    CHECK_EQ(web_frame->render_frame_host(), old_host);
     web_frame->UpdateRenderFrameHost(new_host);
   }
 }