Anim: Add "Add/delete" track operations to NLA context menu

Updating NLA context menu, adding in more relevant track operations (tracks add, tracks add above, tracks delete).

Pull Request: https://projects.blender.org/blender/blender/pulls/114202

scripts/startup/bl_ui/space_nla.py

@@ -353,6 +353,13 @@ class NLA_MT_channel_context_menu(Menu):
         layout = self.layout
 
         layout.operator_menu_enum("anim.channels_move", "direction", text="Track Ordering...")
+
+        layout.separator()
+
+        layout.operator("nla.tracks_add", text="Add Track").above_selected = False
+        layout.operator("nla.tracks_add", text="Add Track Above Selected").above_selected = True
+        layout.separator()
+        layout.operator("nla.tracks_delete")
         layout.operator("anim.channels_clean_empty")