Change score cache eviction time to settings value.

Reduce default eviction time from intended 24 hours (erroneously input
as 24 days) to 20 minutes.

Bug: b/63073866
Test: runtest --path
frameworks/base/packages/SettingsLib/tests/integ/src/com/android/settingslib/wifi/AccessPointTest.java

Change-Id: I89eae2483b9a65a65d7cf5b1151952609b6b7fd7