chore(data-modeling): change file extension COMPASS-9623

[mabaasit]

Description

Checklist

• New tests and/or benchmarks are included
• Documentation is changed or added
• If this change updates the UI, screenshots/videos are added and a design review is requested
• 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)

[Copilot]

Pull Request Overview

This PR changes the file extension for data modeling diagram exports from .compass to .mdm across the application, maintaining consistency between export, import, and testing functionality.

• Updates file extension used for data modeling diagram exports and imports
• Synchronizes test expectations with the new file extension
• Ensures consistency across the data modeling feature

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
packages/compass-e2e-tests/tests/data-modeling-tab.test.ts	Updates test to expect .mdm extension instead of .compass
packages/compass-data-modeling/src/services/open-and-download-diagram.ts	Changes download service to use .mdm extension
packages/compass-data-modeling/src/components/import-diagram-button.tsx	Updates file input to accept .mdm files

[paula-stacho]

Do we have the decision documented somewhere?

[mabaasit]

Do we have the decision documented somewhere?

This change was proposed by Anna during the doc review. I updated the doc to reflect it as well.