Ensure that page titles in social previews use same duplicate name logic as meta titles

[eric-schneider]

As part of #109, we updated the way page meta titles were constructed to avoid duplicate names appearing in the titles. However, it looks like we might not have applied the same logic to the titles used in social previews:

Update

@ErickRamirezDS reported (DOC-4578) that the social preview titles for any of the pages in planning-docs are always suffixed with:

Apache Cassandra Capacity Planning Guide

regardless of whether the page is for C*, DSE or HCD.

These guides have a different component title for each version in antora.yml. So if Antora only surfaces the title of the "latest" version in the UI model, then we might be limited in what we can do. But we should still investigate to confirm. If we're blocked by Antora, then we might need to consider changing the titles to be more generic and rely on the version switcher to fully communicate to the user which guide they're looking at. Note: this also affects the CQL docs, and any other docset that uses the component version aggregator extension in the future.