Ensure object being viewed is an archival object

[andrew-morrison]

Description

This is a fix for a bug I introduced in #1831. I thought, because I was adding code inside this existing if statement...

<% if !@result.instance_of?(DigitalObject) || @has_children %>

...that I didn't need to test that the object being rendered is not a digital object. But, because we don't use digital object components where I work, I had forgotten that if those are present then @has_children is true. In which case, it will cause undefined method `resource_uri' errors.

It only occurs when AppConfig[:pui_search_collection_from_archival_objects] is set to true in config.rb (by default it is false) which is probably why it wasn't picked up in testing.

To fix this, I have added an extra check that the object is an archival object, thus ensuring @result.resource_uri is always defined.

Related JIRA Ticket or GitHub Issue

Fix for http://lyralists.lyrasis.org/pipermail/archivesspace_users_group/2021-June/008532.html

How Has This Been Tested?

On a dev system.

Screenshots (if appropriate):

N/A

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have read the CONTRIBUTING document.
• I have authority to submit this code.
• I have added tests to cover my changes.
• All new and existing tests passed.

[lorawoodford]

Thanks for this @andrew-morrison Looks good to go.