Create pkg specific dirs if they are not available.

When the user clears storage for an app, it's package specific
directories would be deleted, so we need to recreate them when
the app is started again.

Bug: 124058579
Test: manual
Test: atest cts/hostsidetests/appsecurity/src/android/appsecurity/cts/ExternalStorageHostTest.java
Change-Id: I7fcf2c41d16fbcf79fc03b4c4d59baeecd6725ab