Merge branch 'fix-todo-target-path' into 'master'

Fix todo_target_path for todos where target was removed

Fixes #15187 

See merge request !3684

app/assets/javascripts/todos.js.coffee

@@ -59,6 +59,8 @@ class @Todos
 
   goToTodoUrl: (e)->
     todoLink = $(this).data('url')
+    return unless todoLink
+
     if e.metaKey
       e.preventDefault()
       window.open(todoLink,'_blank')

app/helpers/todos_helper.rb

@@ -20,6 +20,8 @@ module TodosHelper
   end
 
   def todo_target_path(todo)
+    return unless todo.target.present?
+
     anchor = dom_id(todo.note) if todo.note.present?
 
     if todo.for_commit?