Remove "Share" from edit menu

Showing the share UI conflicts with the conversation views
inputAccessory toolbar.

Specifically:

- the long press menu acquires first responder
- tapping share presents the activity view
- at this point, the input toolbar is hidden
- launching a share extension hides the activity view, presents the
  share extension (could be the Signal share extension or another app's
  share extension)
- the conversation view (which is rendered behind the share extension)
  regains first responder, causing the input toolbar to appear above the
  share extension

One fix would be to re-implement an interface similar UIMenuController,
which does not require mucking with the responder chain, but that's
going to be more involved.

// FREEBIE

Signal/src/ViewControllers/ConversationView/ConversationViewController.m

@@ -549,6 +549,18 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
     [self.loadMoreHeader autoSetDimension:ALDimensionHeight toSize:kLoadMoreHeaderHeight];
 }
 
+- (BOOL)becomeFirstResponder
+{
+    DDLogDebug(@"%@ in %s", self.logTag, __PRETTY_FUNCTION__);
+    return [super becomeFirstResponder];
+}
+
+- (BOOL)resignFirstResponder
+{
+    DDLogDebug(@"%@ in %s", self.logTag, __PRETTY_FUNCTION__);
+    return [super resignFirstResponder];
+}
+
 - (BOOL)canBecomeFirstResponder
 {
     return YES;

Signal/src/ViewControllers/ConversationView/ConversationViewItem.m

@@ -465,9 +465,6 @@ NSString *NSStringForOWSMessageCellType(OWSMessageCellType cellType)
         [[UIMenuItem alloc] initWithTitle:NSLocalizedString(@"EDIT_ITEM_COPY_ACTION",
                                               @"Short name for edit menu item to copy contents of media message.")
                                    action:self.copyTextActionSelector],
-        [[UIMenuItem alloc] initWithTitle:NSLocalizedString(@"EDIT_ITEM_SHARE_ACTION",
-                                              @"Short name for edit menu item to share contents of media message.")
-                                   action:self.shareTextActionSelector],
         [[UIMenuItem alloc] initWithTitle:NSLocalizedString(@"EDIT_ITEM_MESSAGE_METADATA_ACTION",
                                               @"Short name for edit menu item to show message metadata.")
                                    action:self.metadataActionSelector],
@@ -482,9 +479,6 @@ NSString *NSStringForOWSMessageCellType(OWSMessageCellType cellType)
 - (NSArray<UIMenuItem *> *)mediaMenuControllerItems
 {
     return @[
-        [[UIMenuItem alloc] initWithTitle:NSLocalizedString(@"EDIT_ITEM_SHARE_ACTION",
-                                              @"Short name for edit menu item to share contents of media message.")
-                                   action:self.shareMediaActionSelector],
         [[UIMenuItem alloc] initWithTitle:NSLocalizedString(@"EDIT_ITEM_MESSAGE_METADATA_ACTION",
                                               @"Short name for edit menu item to show message metadata.")
                                    action:self.metadataActionSelector],