clean unused server timestamp

SessionMessagingKit/Messages/Signal/TSIncomingMessage+Conversion.swift

@@ -19,7 +19,6 @@ public extension TSIncomingMessage {
             expiresInSeconds: !isOpenGroupMessage ? expiration : 0, // Ensure we don't ever expire open group messages
             quotedMessage: quotedMessage,
             linkPreview: linkPreview,
-            serverTimestamp: visibleMessage.openGroupServerTimestamp as NSNumber?,
             wasReceivedByUD: true,
             openGroupInvitationName: visibleMessage.openGroupInvitation?.name,
             openGroupInvitationURL: visibleMessage.openGroupInvitation?.url,

SessionMessagingKit/Messages/Signal/TSIncomingMessage.h

@@ -59,7 +59,6 @@ NS_ASSUME_NONNULL_BEGIN
                  expiresInSeconds:(uint32_t)expiresInSeconds
                     quotedMessage:(nullable TSQuotedMessage *)quotedMessage
                       linkPreview:(nullable OWSLinkPreview *)linkPreview
-                  serverTimestamp:(nullable NSNumber *)serverTimestamp
                   wasReceivedByUD:(BOOL)wasReceivedByUD
           openGroupInvitationName:(nullable NSString *)openGroupInvitationName
            openGroupInvitationURL:(nullable NSString *)openGroupInvitationURL

SessionMessagingKit/Messages/Signal/TSIncomingMessage.m

@@ -21,8 +21,6 @@ NS_ASSUME_NONNULL_BEGIN
 
 @property (nonatomic, getter=wasRead) BOOL read;
 
-@property (nonatomic, nullable) NSNumber *serverTimestamp;
-
 @end
 
 #pragma mark -
@@ -52,7 +50,6 @@ NS_ASSUME_NONNULL_BEGIN
                  expiresInSeconds:(uint32_t)expiresInSeconds
                     quotedMessage:(nullable TSQuotedMessage *)quotedMessage
                       linkPreview:(nullable OWSLinkPreview *)linkPreview
-                  serverTimestamp:(nullable NSNumber *)serverTimestamp
                   wasReceivedByUD:(BOOL)wasReceivedByUD
           openGroupInvitationName:(nullable NSString *)openGroupInvitationName
            openGroupInvitationURL:(nullable NSString *)openGroupInvitationURL
@@ -77,7 +74,6 @@ NS_ASSUME_NONNULL_BEGIN
     _authorId = authorId;
     _sourceDeviceId = sourceDeviceId;
     _read = NO;
-    _serverTimestamp = serverTimestamp;
     _wasReceivedByUD = wasReceivedByUD;
     _notificationIdentifier = nil;