fix(compass-schema): update export modal COMPASS-9065

[paula-stacho]

Description

The modal was not up to date with the latest designs.
Other changes:

• renaming extendedJSON format to expandedJSON to prevent confusion
• wrapping MongoDB's schema with $jsonSchema so that it can be directly used for the validator (most likely use case)

Checklist

• New tests and/or benchmarks are included
• Documentation is changed or added
• I have signed the MongoDB Contributor License Agreement (https://www.mongodb.com/legal/contributor-agreement)

Motivation and Context

• Bugfix
• New feature
• Dependency update
• Misc

Open Questions

Dependents

Types of changes

• Backport Needed
• Patch (non-breaking change which fixes an issue)
• Minor (non-breaking change which adds functionality)
• Major (fix or feature that would cause existing functionality to change)