Fix: Add remoteAuthS3 type to DiscussionEmbedConfig Interface

[chrisjtang]

Description

These changes add the remoteAuthS3 type to the DiscussionEmbedConfig interface.

Motivation and Context

#151

How Has This Been Tested?

Using https://github.com/chrisjtang/foodandstuff/tree/typescript, the original bug was reproduced and fixed with the change in this PR.

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
  • I have updated the documentation accordingly.
• All new and existing tests passed.

[Hovspian]

lgtm