Fix IIIF manifests when the presenter model is a SolrDocument

[dlpierce]

Summary

hydra_model is already a class, don't call class on it

Guidance for testing, such as acceptance criteria or new user interface behaviors:

• Manifests in koppie or Nurax PG include a sequence section with URLS for the IIIF endpoint.
• or
• The universal viewer displays the work's images.

Type of change (for release notes)

• notes-valkyrie Valkyrie Progress

Detailed Description

Fix IIIF manifests when the presenter model is a SolrDocument. hydra_model already returns a class. Calling class on it breaks the Hyrax::Resource subclass determination causing the wrong code path to be used resulting in a manifest without any images.

@samvera/hyrax-code-reviewers

[orangewolf]

looks great