Update EconomicPolicy loading.

1. Fix bug in CompleteEconomicPolicy that returned the incorrect hard
   consumption limit.
2. Add lower limits on the policy values to ensure valid values that
   allow for reasonable operation.

Bug: 240162678
Test: atest frameworks/base/services/tests/mockingservicestests/src/com/android/server/tare
Test: atest frameworks/base/services/tests/servicestests/src/com/android/server/tare
Change-Id: I89bae508930564ee3a082027dfb97ec517101dd0