add null pointer check for CarrierPrivilegeRules

1. add null pointer check for uiccCarrierPrivilegeRule
2. unregister provision listener when CarrierPrivilegeRule was
disposed.

Bug: 133501845
Test: Manual
Merged-In: Ia30b8b8f8c916063b55bd422cf0b67cfa2decdc5
Change-Id: Ia30b8b8f8c916063b55bd422cf0b67cfa2decdc5
(cherry picked from commit 2727346f789b7c08811f69ece058f7952509c209)