update unit names

[gumaerc]

What are the relevant tickets?

https://github.com/mitodl/hq/issues/4748

Description (What does it do?)

This PR updates unit names in offered_by.json and platforms.json according to what is described in the attached issue.

How can this be tested?

• Spin up mit-open on this branch
• Run the following commands, one at a time:

  docker compose exec web ./manage.py loaddata platforms offered_by
  docker compose exec web ./manage.py update_offered_by
  docker compose exec web ./manage.py update_platforms
  docker compose exec web ./manage.py backpopulate_resource_channels --overwrite
  docker compose exec web ./manage.py recreate_index --all

• After all of the commands above have been run successfully, test the following:
  • Visit http://localhost:8063/units
  • Click any of the units described in the issue above and verify that the channel page has been updated with the new information
  • Visit http://localhost:8063/search and scroll down to the "Offered By" facet and expand it
  • Verify that the names have been updated in the facet
  • Filter by the facets one at a time, and in each one click a card and verify that the name has been updated in the learning resource drawer
  • Visit http://localhost:8063/api/v1/learning_resources_search/?limit=12&sortby=new and verify that the platforms and offered_by sections include the updated names

Checklist:

• After the code is deployed to each environment, run the following in a Heroku shell (heroku run -a <app name> /bin/bash):
  • [ ] ./manage.py loaddata platforms offered_by
  • [ ] ./manage.py update_offered_by
  • [ ] ./manage.py update_platforms
  • [ ] ./manage.py backpopulate_resource_channels --overwrite
  • [ ] ./manage.py recreate_index --all