Artdaq source/destination tables should transparently deal with broken links
When an artdaq BoardReader context is disabled, the corresponding source entries in the EventBuilder should handle the broken link transparently.
This "Auto-detect and handle disabled context" feature should also apply to the following links:
BoardReader destination link to EventBuilder
EventBuilder destination link to DataLogger
DataLogger source link to EventBuilder
DataLogger destination link to Dispatcher
Dispatcher source link to DataLogger