remove useless expiration flag in data message

SessionMessagingKit/Messages/Visible Messages/VisibleMessage.swift

@@ -103,14 +103,6 @@ public final class VisibleMessage : Message {
         // TODO: Contact
         // Open group invitation
         if let openGroupInvitation = openGroupInvitation, let openGroupInvitationProto = openGroupInvitation.toProto() { dataMessage.setOpenGroupInvitation(openGroupInvitationProto) }
-        // Expiration timer
-        // TODO: We * want * expiration timer updates to be explicit. But currently Android will disable the expiration timer for a conversation
-        // if it receives a message without the current expiration timer value attached to it...
-        var expiration: UInt32 = 0
-        if let disappearingMessagesConfiguration = OWSDisappearingMessagesConfiguration.fetch(uniqueId: threadID!, transaction: transaction) {
-            expiration = disappearingMessagesConfiguration.isEnabled ? disappearingMessagesConfiguration.durationSeconds : 0
-        }
-        dataMessage.setExpireTimer(expiration)
         // Group context
         do {
             try setGroupContextIfNeeded(on: dataMessage, using: transaction)