AchievedAtDate for milestone is not preserved when case is reopen

RHPAM-2556 provides case reopen capability.

After test the solution it was found it doesn't preserve the AchievedAtDate. AchievedAt date AFTER reopen is not equal to the achievedAt date BEFORE reopen. Instead, it is the timestamp of the reopen call operation. This is unexpected.

We are working to provide a test case, right now it should be shown with:

before reopen milestone:

CaseMilestone

{name='Create Milestone Reopen Test', achieved=true, achievedAt=Thu Feb 27 09:01:11 GMT 2020}

Put a Thread.sleep(10s) here followed by reopenCase call

after reopen milestone:

CaseMilestone

{name='Create Milestone Reopen Test', achieved=true, achievedAt=Thu Feb 27 09:01:22 GMT 2020}

The Milestone is the same, but the achievedAt date is not.