Destroy SdkSandbox User Data

In installd's destroyUserData function we need to take care of destroying the sdksandbox directories associated with user data
alongwith some minor test changes in installd

Bug: 222698779
Test: atest DestroyUserDataTest
Ignore-AOSP-First: Feature is being developed in internal branch
Change-Id: I11248f6bed2740f7605a6d7294d266e0bfefcfef