Skip from copying preopted files if device is undecrypted

After applies issue 78613232 patch (create symlink in init.rc),
we found device boots to home screen fail.

When device is FDE (Full Disk Encryption) and user sets the
Password/Pattern/PIN to lock phone and then reboot the device,
data partition will be mounted as tmpfs (256MB) until device
is unlocked after user inputs Password/Pattern/PIN.

During device boot-up process, PMS (Package Manager Service) will
execute requestCopyPreoptedFiles when device first boots, and it
may cause device fails to boot to home screen because PMS copies
larger system_b (about 500MB) to smaller tmpfs (tmpfs is only 256MB)
before device is decrypted.

We suggest that PMS doesn't execute requestCopyPreoptedFiles when
device is undecrypted during first boot.

Bug: 78613232

Test: Device boot up to launcher normally.
Test: APPs work normally after A/B upgrade.

Change-Id: I893e0e217a59577299e97adfbf5dc7762dffda7c