[Cherry-pick] DYN-9903: Avoid using closed Window as EditWindow owner

[github-actions]

Cherry-pick of #17014 to RC4.1.0_master

Purpose

Crash Fix

dynamoViewModel.Owner is a mutable property that gets temporarily redirected to child windows (Package Manager, Preferences) so dialogs opened from within those windows are centered correctly. Neither window restored the owner back to the main DynamoView on close, leaving a stale reference to a closed window. Any subsequent EditWindow construction (node rename, note edit) would crash with InvalidOperationException: Cannot set owner to a Window that has been closed.

Added 2 tests

WhenDynamoViewModelOwnerIsClosedWindowThenEditWindowDoesNotThrow

• Directly reproduces the crash: sets ViewModel.Owner to a closed Window (what PackageManager/Preferences leaves behind), then constructs EditWindow.
• Would have failed before the IsLoaded guard added to EditWindow.xaml.cs:36 with InvalidOperationException: Cannot set owner to a Window that has been closed.

WhenChildWindowClosesOwnerIsRestoredToDynamoView

• Verifies the contract that prevents the bug: when a child window closes, ViewModel.Owner must be back to the main DynamoView.
• Validates the pattern implemented in HandlePackageManagerWindowClosed and PreferencesView.CloseButton_Click

Declarations

Check these if you believe they are true

• Is documented according to the standards
• The level of testing this PR includes is appropriate
• Changes to the API follow Semantic Versioning and are documented in the API Changes document.

Release Notes

Fixes a crash (InvalidOperationException) when renaming a node after the Package Manager or Preferences window had been opened and closed.

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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