Add drupal/core JS dependency for anon user view.

[alxp]

GitHub Issue: OpenSeadragon viewer does not display for Anonymous on Drupal 9

What does this Pull Request do?

Out of the box Drupal 9, the OpenSeadragon viewer is not shown when viewing an Image object as Anonymous.

What's new?

Drupal 9 does not include the drupal/core JS library by default for anonymous users. This PR adds this dependency.

How should this be tested?

From a fresh install on Drupal 9:

1. Apply the patch and clear the Drupal cache.
2. Create a Repository Object and select Image for the Model and Resource Type, and OpenSeadragon for the display hint.
3. Add a Media of type Image.
4. Log out and view the object. The OpenSeadragon viewer should appear where it did not before.

Interested parties

Fix by @ppound

@Islandora/8-x-committers,

[seth-shaw-unlv]

Works as advertised. 👍