feat: add Unbox for symmetry with IntoBox

[giladchase]

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[giladchase]

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• feat: use local_into_box #9046
• feat: add Unbox for symmetry with IntoBox #9080 👈 (View in Graphite)
• Add IntoBox instead of into_box in lowering #8967
• main

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[orizi]

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---

a discussion (no related file):
remove "unbox" from the set of movable functions - as no longer required listing.

[orizi]

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[orizi]

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