Data Entry Control in Asset Template should indicate tag doesn't exists

In Axiom v24, if you add a Data Entry Control to an Asset Template, the control will show up in each asset pane, regardless of whether or not that tag exists. If someone tried to enter a value, you get an unhandled error about not being able to find a server address. Assets that don't have the tag should have the Data Entry Control grayed out. Similar to how if you have a Trend in an Asset Template, the trend line doesn't show up for assets that don't have that tag.