FDN cache shall be reset when receiving the file change notification

The issue happens in the expected sequence 1.2 (REFRESH, File Change
Notification) of 3GPP 31.124 TC 27.22.4.7. The FDN cache is not reset
when the file change event for FDN is notified, so no one can know the
updated FDN in Android layer.

Bug: 29085691
Change-Id: I339c85692b8b9d57c2899e8bde71b33e326d523c