Fix crash around account attributes update when unregistered.

SignalServiceKit/src/Account/TSAccountManager.m

@@ -649,6 +649,10 @@ NSString *const TSAccountManager_NeedsAccountAttributesUpdateKey = @"TSAccountMa
 }
 
 - (AnyPromise *)updateAccountAttributesIfNecessary {
+    if (!self.isRegistered) {
+        return [AnyPromise promiseWithValue:@(1)];
+    }
+
     NSDate *_Nullable updateRequestDate =
         [self.dbConnection objectForKey:TSAccountManager_NeedsAccountAttributesUpdateKey
                            inCollection:TSAccountManager_UserAccountCollection];