Skip expiration for calls.

// FREEBIE

src/Devices/OWSReadReceiptsProcessor.m

@@ -120,17 +120,21 @@ NSString *const OWSReadReceiptsProcessorMarkedMessageAsReadNotification =
                     // * Don't update expiration; we'll do that in the next statement.
                     [interaction markAsReadWithTransaction:transaction sendReadReceipt:NO updateExpiration:NO];
 
+                    if ([interaction isKindOfClass:[TSMessage class]]) {
+                        TSMessage *otherMessage = (TSMessage *)interaction;
+
                         // Update expiration using the timestamp from the readReceipt.
-                    [OWSDisappearingMessagesJob setExpirationForMessage:(TSMessage *)interaction
+                        [OWSDisappearingMessagesJob setExpirationForMessage:otherMessage
                                                         expirationStartedAt:readReceipt.timestamp];
 
                         // Fire event that will cancel any pending notifications for this message.
                         dispatch_async(dispatch_get_main_queue(), ^{
                             [[NSNotificationCenter defaultCenter]
                                 postNotificationName:OWSReadReceiptsProcessorMarkedMessageAsReadNotification
-                                          object:(TSMessage *)interaction];
+                                              object:otherMessage];
                         });
                     }
+                }
             }];
 
             // If it was previously saved, no need to keep it around any longer.