Fix annotation for RichTextTable component

[dat-boris]

Summary:

Previously although RichTextTable display properly, the annotation
didn't work.

This PR is a result of a bunch of learning on how the registry works,
and realize a bunch of small things that we did wrong and need to hook up
properly. These will be documented in our documentation [1].

[1] https://khanacademy.atlassian.net/wiki/spaces/INFRA/pages/2373714068/Label+Studio+Frontend+guide#Note%3A-Adding-new-components-need-to-update-registry-and-Mobx-types

Issue: https://khanacademy.atlassian.net/browse/DI-533

Test plan:

• yarn start and goes to https://localhost:3000, and try out the
  annotation.

[dat-boris]

Huh - the E2E test failure is worth debugging (I will circle back tmr)

  1) Date Time
       Check DateTime holds state between annotations and saves result:
     TypeError: s.updateGlobalOffsets is not a function
      at /home/runner/work/label-studio-frontend/label-studio-frontend/e2e/plugins/errorsCollector.js:175:16

I have no idea what the cypress test failure is, looks like it is a dependency failure.

[wwells]

praise: Thank you for the clear linked FE documentation. Great anchor as we start building out more documentation over the coming sprints. Especially key for our team of not FE engineers ;)

[wwells]

PS: I added a placeholder note to the one-pager that once this is deployed we should validate using this by updating existing workflows and making sure our import/export commands still work....

[dat-boris]

Woohoo, check pass! Landing now.