Makes sure caches are bust when fetching feedback/activity

IE9 doesn't seem to fire the requests anew; adding an explicit cache: false
(which will append a unique timestamp to the request) will make sure IE9 really
does request fresh data (instead of serving the same old data that likely has
changed already when heavily moderating feedback.

Bug: 46797
Change-Id: I0bffc61e6203c91682d70e5c1dae5134af044ca5
Merge "Makes sure caches are bust when fetching feedback/activity"