feat(social-media/publish-post): Expose original error

[jnv]

Description

This adds original field to social-media/publish-post and prepares new field code as a normalized error code across providers (code isn't yet implemented but can be continuously added to the maps).

Motivation and Context

Types of changes

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

Checklist:

• [x] I have read the CONTRIBUTING document.
• [x] I haven't repeated the code. (DRY)
• [x] I have added tests to cover my changes.
• [x] All new and existing tests passed.