Single lingual JSON:API Extras proxy bug

[Decipher]

Describe the bug
When a Drupal 9 site doesn't have the configurable_language resource exposed, but has data for the resource in the jsonapi_resource_config resource as well as the latest version of Druxt with the API proxy enabled, you will encounter the following error:

 FATAL  Cannot read property 'attributes' of undefined                                                                                                                                                          09:28:29

  at node_modules/druxt/dist/druxt.ssr.js:367:222
  at Array.map (<anonymous>)
  at ModuleContainer.DruxtNuxtModule (node_modules/druxt/dist/druxt.ssr.js:367:209)
  at processTicksAndRejections (internal/process/task_queues.js:95:5)
  at async ModuleContainer.addModule (node_modules/@nuxt/core/dist/core.js:239:20)
  at async ModuleContainer.DruxtSiteNuxtModule (node_modules/druxt-site/dist/druxt-site.ssr.js:71:5)
  at async ModuleContainer.addModule (node_modules/@nuxt/core/dist/core.js:239:20)
  at async ModuleContainer.ready (node_modules/@nuxt/core/dist/core.js:51:7)
  at async Nuxt._init (node_modules/@nuxt/core/dist/core.js:478:5)

To Reproduce
Steps to reproduce the behavior:

1. Setup a site with the requirements provided above...

Expected behavior
No errors, site should work.

Media
N/A

Your Environment (please complete the following information):
N/A

Additional context
N/A