[ios] Enable badged reading list by default

This CL enables the badged reading list by default.

Bug: 848358

Change-Id: I23e371c2de66f39c6e2b856c802451129911140f
Reviewed-on: https://chromium-review.googlesource.com/1088191Reviewed-by: David Trainor <dtrainor@chromium.org>
Reviewed-by: edchin <edchin@chromium.org>
Commit-Queue: edchin <edchin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#565085}

components/feature_engagement/public/feature_constants.cc

@@ -70,7 +70,7 @@ const base::Feature kIPHNewTabTipFeature{"IPH_NewTabTip",
 const base::Feature kIPHNewIncognitoTabTipFeature{
     "IPH_NewIncognitoTabTip", base::FEATURE_DISABLED_BY_DEFAULT};
 const base::Feature kIPHBadgedReadingListFeature{
-    "IPH_BadgedReadingList", base::FEATURE_DISABLED_BY_DEFAULT};
+    "IPH_BadgedReadingList", base::FEATURE_ENABLED_BY_DEFAULT};
 #endif  // defined(OS_IOS)
 
 }  // namespace feature_engagement