Fix instance where PNI may be accessed too early.

app/src/main/java/org/thoughtcrime/securesms/contacts/paged/ContactSearchViewModel.kt

@@ -28,12 +28,13 @@ class ContactSearchViewModel(
   private val selectionLimits: SelectionLimits,
   private val contactSearchRepository: ContactSearchRepository,
   private val performSafetyNumberChecks: Boolean,
-  private val safetyNumberRepository: SafetyNumberRepository = SafetyNumberRepository(),
   private val arbitraryRepository: ArbitraryRepository?,
   private val searchRepository: SearchRepository,
   private val contactSearchPagedDataSourceRepository: ContactSearchPagedDataSourceRepository
 ) : ViewModel() {
 
+  private val safetyNumberRepository: SafetyNumberRepository by lazy { SafetyNumberRepository() }
+
   private val disposables = CompositeDisposable()
 
   private val pagingConfig = PagingConfig.Builder()