"you have been assigned a role" notification send when a dataset is published

[pameyer]

Originally noticed in #3998, but appears unrelated to code changes there.

Depositor with dsContributor creates dataset (with no restricted files), (optionally) submits for review, Curator publishes dataset. Depositor receives notification that the dataset has been publish, and notification that they have been assigned a role (which isn't necessary to notify them about in this case).

[scolapasta]

So, in cleaning up notifications for Publish generally, @TaniaSchlatter, @matthew-a-dunlap and I decided that we should do away with this notification and just include these users in the Publish Dataset notification.

In other words, the idea is to have 1 notification that gets sent out to all interested parties (those with ViewUnpublishedDataset and DownloadFile permissions) when the dataset is published. This should hopefully clear up some of the confusion.

We still have the "you have been granted file access" notification if you've been granted DownloadFile permission to a specific file.

Since @matthew-a-dunlap has been doing clean up on that Publish Dataset notification for #3998 we're including this in that.

[matthew-a-dunlap]

Here are some extra notes to help with QA:
Dataset publish notification goes to users with these permissions:

• Permission.ViewUnpublishedDataset
• Permission.DownloadFile

You should see these notifications in this order when creating a dataset, including when assign a dataset for review:

• Dataset created
• Dataset published

Rsync timing should continue to work as intended (notification going out after things are done). Normal notifications should work in the same way.

Note: The role added notification was kept in the first commit but should have been removed. This has been edited to reflect that.