Use Dataset Thumbnail in Open Graph metadata: SPA

[jp-tosca]

Overview of the Feature Request

The PR #5621 included a solution so the tag og:image (OpenGraph) uses the thumbnail if it is available or the DV logo. We discussed during the standup meeting that this solution will work only for JSF so we probably could move this logic into the endpoint so the JSP and the JSF version share a solution.

For now, we moved forward #5621 but should keep track of this for the SPA.

@GPortas @ekraffmiller should we leave this issue here or in front-ed?