Fix dependency error during testing
Fix dependency error during testing

Error was:
```
NoMethodError:
undefined method `html_escape' for
<RSpec::ExampleGroups::BlacklightHelper::RenderIndexFieldValue::MetadataIndexLinks::DescriptionTesim:0x007fd95fcb0d28>
...
 ./app/helpers/sufia/sufia_helper_behavior.rb:125:in `iconify_auto_link'
```

In application usage, all invocations are inside a template context, so
the methods happen to be available.  But accounting for the requirement
is still worthwhile.

samvera/hyrax,samvera/hyrax,samvera/hyrax,samvera/hyrax