[WC-1301]: update structure preview for data grid 2

[r0b1n]

Description

Pull request checklist

• All new and existing tests passed
• I run lint command locally and it doesn’t give errors
• PR title properly formatted [XX-000]: description
• Added record to packages' CHANGELOG.md
• Bumped package version in package.json and package.xml
• Added a link to related project PRs (atlas, pluggable-widgets-tools, testProject, etc.) (optional)
• Created docs PR to mendix/docs and added a link (optional)

Pull request type

• No code changes (changes to documentation, CI, metadata, etc)
• Dependency changes (any modification to dependencies in package.json)
• 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)
• Test related change (New E2E test, test automation, etc.)

What should be covered while testing?

This also includes a small fix for WC-1562 for HTML Element. Make sure structure preview for DataGrid 2 and HTML Element works in:

• Below 9.18 (old structure preview)
• At 9.18 (old structure preview)
• At 9.19 (old structure preview)
• At 9.20+ (new structure preview with one global datasource header)

This is needed because of API transitions in 9.18 - 9.20, so we want to cover all cases.