FYI: This needs to be rebuilt in Piwik 3. Created https://github.com/piwik/piwik/issues/9972
It currently shows like this:
To be a bit more clear can we maybe write something like "Goal $goalName conversions by type of visit are not shown ..." and "Conversions overview by type of visit is not shown"
Maybe we could even still show the headline as usual and below write "there is no data for this report because there were no conversions ... "
Now the headline should still be visible when the message is shown.