MDL-47758 tool_monitor: prevent DB error when revisiting a delete URL
MDL-47758 tool_monitor: altered behat tests so they pass
MDL-47361 tooL_monitor: string and UI changes
MDL-47361 tool_monitor: altered behat tests so they pass
MDL-47810 tool_monitor: action_link when there is only 1 option

When the rule plugin is not a module you can subscribe
to it without having to select to which module instance
you want to subscribe, so there is no need to display
a drop down menu.