[network-audit] Add test coverage for the New Tab Page

As reported in brave/brave-browser#20501,
the NTP was making outbound requests to ftx.com at startup without
user opt-in, and the network-audit didn't catch that case because
it was NOT loading a NTP as part of the different checks it does
at BraveNetworkAuditTest.BasicTests.

This patch adds explicit test coverage for that case by loading
brave://newtab and waiting 5 minutes, like with the other checks.

Resolves brave/brave-browser#20504

browser/net/brave_network_audit_browsertest.cc

@@ -274,6 +274,10 @@ IN_PROC_BROWSER_TEST_F(BraveNetworkAuditTest, BasicTests) {
   ASSERT_TRUE(ui_test_utils::NavigateToURL(browser(), GURL("brave://welcome")));
   WaitForTimeout(kMaxTimeoutPerLoadedURL);
 
+  // Load the NTP to check requests made from the JS widgets.
+  ASSERT_TRUE(ui_test_utils::NavigateToURL(browser(), GURL("brave://newtab")));
+  WaitForTimeout(kMaxTimeoutPerLoadedURL);
+
   // Load a simple HTML page from the test server.
   GURL simple_url(embedded_test_server()->GetURL("/simple.html"));
   ASSERT_TRUE(ui_test_utils::NavigateToURL(browser(), simple_url));

package.json

@@ -19,7 +19,7 @@
     "update_patches": "node ./build/commands/scripts/commands.js update_patches",
     "apply_patches": "node ./build/commands/scripts/commands.js apply_patches",
     "start": "node ./build/commands/scripts/commands.js start",
-    "network-audit": "npm run test brave_network_audit_tests -- --ui-test-action-timeout=330000 --test-launcher-timeout=1300000",
+    "network-audit": "npm run test brave_network_audit_tests -- --ui-test-action-timeout=330000 --test-launcher-timeout=1600000",
     "push_l10n": "node ./build/commands/scripts/commands.js push_l10n",
     "pull_l10n": "node ./build/commands/scripts/commands.js pull_l10n",
     "chromium_rebase_l10n": "node ./build/commands/scripts/commands.js chromium_rebase_l10n",