These messages are always already read.
Reminder, there are two types of read receipts:
1. One informs our linked devices that we've read a message on another
device.
2. The other informs the sender that we've read their message.
This change is about the latter, we'll continue to send the former to
ourself.
The proximate cause for this change was a failing assert in
OWSMessageSender#handleSendToMyself:(TSOutgoingMessage *)outgoingMessage
The assert was failing because we were sending a message to ourself
which had no body or attachment (the sender-read receipt). Rather than
filtering them out from the message sender, we should never ask the
message sender to do nonsense work (send a senderReadReceipt to ourself)
// FREEBIE
To avoid blocking launch, file protection is now updated async for most
moved files. Out of paranoia, the database files are also update
redundantly on a sync code path.
It's still critical that we update permissions recursively for two
reasons:
1. Updating a containing directories FileProtection does not affect
existing files in that directory.
2. Because we've changed the containers default file protection level
(from unspecified to NSFileProtectionComplete), some existing files
will have there file protection updated upon launching Signal 2.20.
It's not clear to me which files this affects, and I haven't found
any relevant documentation, but from observation, it seems to affect
any top-level files in the container. Regardless, we're now doing the
right thing: after launching 2.20, ensure all file permissions are
what we expect.
Also removed no-op file protection on legacy db files. They've already
been moved by the time this method runs in AppSetup.
// FREEBIE
OWSReadReceiptManager is not `init` on the main thread; however, because
it "schedules" it's own processing during init.
I considered dispatching to main, but since AppReadiness already *can*
resolve async if the app isn't yet ready, it should be no less safe to
also dispatch async when it's off the main thread.
// FREEBIE
