Fix actor paste parent selection in hierarchy and root context

[Gopmyc]

Description

This PR fixes actor copy/paste behavior in the Hierarchy panel.

Previously, pasting a copied actor could reattach it using the copied actor's original parent when pasting into root-level contexts. As a result, paste did not always respect the destination location.

This change makes paste behavior explicit:

• Paste always uses the destination context (same parent as target actor, or root when target is root/null)
• No implicit fallback to the copied actor's original parent during paste

Additionally, this PR updates one DuplicateActor bind call in Hierarchy.cpp to match the updated method signature and restore clean compilation.

Related Issue(s)

Fixes #781

Review Guidance

Please review:

• EditorActions::DuplicateActor new explicit control for source-parent reuse
• EditorActions::PasteActor now disabling source-parent fallback
• Hierarchy duplicate action bind updated for signature compatibility

Expected manual behavior:

1. Copy a child actor
2. Paste on a root-level actor
3. Pasted actor appears under the destination parent context (not under the copied actor's former parent)

Screenshots/GIFs

N/A

AI Usage Disclosure

N/A

Checklist

• My code follows the project's code style guidelines
• When applicable, I have commented my code, particularly in hard-to-understand areas
• When applicable, I have updated the documentation accordingly
• My changes don't generate new warnings or errors
• I have reviewed and take responsibility for all code in this PR (including any AI-assisted contributions)