SOC-3599 Test failure at ActivityStorageImplTestCase.testActivityOrderByPostedTime on the 1st of month

Problem analysis:
* Activities of past month are not ordered

Fix description:
* Add unit test to check ActivityOrderByPostedTime on the 1st of month
* Order activities in each month by posting time
Merge commit 'e80aa43a9084cb50891f3cca86cadf8f2acb1bf9' into HEAD