Config Merge on wren_social_data with Remote Theme Fails

[Foggalong]

Describe the bug
The wren_social_data YAML in the theme's config isn't merged into the user's config when they're using Wren through jekyll-remote-theme remotely.

To Reproduce
Steps to reproduce the behaviour:

1. Set remote theme: jekyll-wren
2. Remove wren_social_data from _config.yml
3. Scroll down to footer
4. See broken social buttons

Expected behaviour
Would expect Jekyll to pick up the wren_social_data YAML from the theme's config so that the user doesn't have to have the data saved in theirs. This happen if using Wren's gem but not when using the theme remotely.