Handle title element attributes by redirecting to title-content element

[DawidKossowski]

🚀 Summary

The title element in the model doesn't have a corresponding view element. Only its child title-content is converted to <h1> in the view. When attributes are set on the title element, the downcast conversion fails because there's no view element to apply them to.

Added a downcast converter that intercepts attribute changes on title elements and redirects them to the title-content corresponding view element. This ensures that attributes set on title in the model are correctly rendered in the view without causing conversion errors.

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📌 Related issues

• Closes #000

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💡 Additional information

These changes are required for the AI feature, as it handles elements by adding the $elementId attribute to each one.

[scofalik]

LGTM.

I dislike that we need to make a change in downcastdispatcher.ts because title feature is incorrectly written. But it is what it is. Title feature breaks the rule that every model element should be mapped to a counterpart in the view. The feature should be fixed. I will add this as a followup ticket.

[scofalik]

#19484