fixing schema designer perf

[aasimkhan30]

Pull Request Template – vscode-mssql

Description

Fixes #19168, Fixes #19474

1. Updates fluent ui react to the latest version. This brings the list component out of the preview so we don't need an additional package "@fluentui/react-list-preview" to include it.
2. Renames the GetScript API to GetDefinition to better match the UI text.
3. Updated the target table dropdown in foreing key editor to Searchable dropdown to keep it consistent with other dropdowns.
4. Making sure we turn off react flow virtualization when we export the diagram as an image so that we are rendering all then nodes.
5. When generating report for the changes, I am changing from a modal dialog that blocks the diagram to a vscode notification.
   Before:

After: (Publish button gets disable as we don't want users to press it twice.

Code Changes Checklist

• New or updated unit tests added
• All existing tests pass (npm run test)
• Code follows contributing guidelines
• Telemetry/logging updated if relevant
• No regressions or UX breakage

Reviewers: Please read our reviewer guidelines

[github-actions]

PR Changes

Category	Main Branch	PR Branch	Difference
Code Coverage	58.72%	58.60%	⚪ 0.00%
VSIX Size	15305 KB	15297 KB	⚪ -8 KB ( 0% )
Webview Bundle Size	3692 KB	3616 KB	🟢 -76 KB ( -2% )