clean up unused code

Session/Conversations/ConversationVC+Interaction.swift

@@ -591,11 +591,6 @@ extension ConversationVC : InputViewDelegate, MessageCellDelegate, ContextMenuAc
     }
     
     func delete(_ viewItem: ConversationViewItem) {
-        if (!self.isUnsendRequestsEnabled) {
-            viewItem.deleteAction()
-            return
-        }
-        
         guard let message = viewItem.interaction as? TSMessage else { return self.deleteLocally(viewItem) }
         
         // Handle open group messages the old way

Session/Conversations/ConversationVC.swift

@@ -5,7 +5,6 @@
 // • Remaining search glitchiness
 
 final class ConversationVC : BaseVC, ConversationViewModelDelegate, OWSConversationSettingsViewDelegate, ConversationSearchControllerDelegate, UITableViewDataSource, UITableViewDelegate {
-    let isUnsendRequestsEnabled = true // Set to true once unsend requests are done on all platforms
     let thread: TSThread
     let focusedMessageID: String? // This is used for global search
     var focusedMessageIndexPath: IndexPath?

Session/Conversations/ConversationViewModel.h

@@ -122,8 +122,6 @@ static const int kYapDatabaseRangeMaxLength = 250000;
 
 - (void)ensureDynamicInteractionsAndUpdateIfNecessary:(BOOL)updateIfNecessary;
 
-- (void)clearUnreadMessagesIndicator;
-
 - (void)loadAnotherPageOfMessages;
 
 - (void)viewDidResetContentAndLayout;

Session/Conversations/ConversationViewModel.m

@@ -517,37 +517,6 @@ NS_ASSUME_NONNULL_BEGIN
     }
 }
 
-- (void)clearUnreadMessagesIndicator
-{
-    OWSAssertIsOnMainThread();
-
-    // TODO: Remove by making unread indicator a view model concern.
-    id<ConversationViewItem> _Nullable oldIndicatorItem = [self.viewState unreadIndicatorViewItem];
-    if (oldIndicatorItem) {
-        // TODO ideally this would be happening within the *same* transaction that caused the unreadMessageIndicator
-        // to be cleared.
-        [LKStorage writeWithBlock:^(YapDatabaseReadWriteTransaction *_Nonnull transaction) {
-            [oldIndicatorItem.interaction touchWithTransaction:transaction];
-        }];
-    }
-
-    if (self.hasClearedUnreadMessagesIndicator) {
-        // ensureDynamicInteractionsForThread is somewhat expensive
-        // so we don't want to call it unnecessarily.
-        return;
-    }
-
-    // Once we've cleared the unread messages indicator,
-    // make sure we don't show it again.
-    self.hasClearedUnreadMessagesIndicator = YES;
-
-    if (self.dynamicInteractions.unreadIndicator) {
-        // If we've just cleared the "unread messages" indicator,
-        // update the dynamic interactions.
-        [self ensureDynamicInteractionsAndUpdateIfNecessary:YES];
-    }
-}
-
 #pragma mark - Storage access
 
 - (void)uiDatabaseDidUpdateExternally:(NSNotification *)notification