Some email notifications have empty "" in subject (bug in #9056)

[qqmyers]

What steps does it take to reproduce the issue?
#9056 changed several messages to include the dataset diplayname in quotes in the message. However the PR code assumes that the object being sent to the message is the dataset and the displayname is left blank when the object is the datasetversion. (FWIW: The bug was introduced during review in trying to avoid a null pointer for messages that don't use either of these object types.)

• What happens?
  When messages are sent - they say things like Qualitative Data Repository: Dataset "" Status Change
  Which version of Dataverse are you using?
  5.12.1

PR to follow

[pdurbin]

I just tweaked the title of this issue because (based on the PR) the fix only seems to affect email notifications.

Thank you @kcondon for helping me find it! And thanks to @qqmyers for the fix, of course.

I was affected by this bug when I re-published my dataset at https://doi.org/10.7910/DVN/TJCLKP and here's a screenshot:

As of this writing Harvard Dataverse is running 5.12.1. The fix has been merged and will be in the next release.