Fix security_page_test.js incorrect feature state assumption

Enforces state of enableSecurityKeysSubpage feature flag during tests

Bug: 1108551
Change-Id: I858fdb78096c31640a7ce50aa73468df58dab5e7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2317206Reviewed-by: Sean Harrison <harrisonsean@chromium.org>
Commit-Queue: Theodore Olsauskas-Warren <sauski@google.com>
Cr-Commit-Position: refs/heads/master@{#791730}

chrome/test/data/webui/settings/security_page_test.js

@@ -33,6 +33,7 @@ suite('CrSettingsSecurityPageTestWithEnhanced', function() {
 
   suiteSetup(function() {
     loadTimeData.overrideValues({
+      enableSecurityKeysSubpage: true,
       safeBrowsingEnhancedEnabled: true,
     });
   });