Fixed format of cmd user report-system-user-package-whitelist-problems

Commit 79b6931b changed "whitelisted"
to "allowlisted", which broke some tests.

Fixes: 413820637
Test: atest SystemPackagesPreInstallAllowlistTest
Flag: EXEMPT Test fix only

Change-Id: Ib34d08f488be874996fae83b071513d4bc6f51f5