404 on datacite create from push protected master branch

[mpsonntag]

Trying to create a datacite file via the "Add DataCite file" button from a push protected master branch results in a 404 page.

The page should switch the "Add DataCite file" button to disabled if the master branch is push protected and the tooltip should display appropriate information for this case.

[mpsonntag]

Thanks to @JuliaSprenger for bringing this issue to our attention.