refactor: simplify hitbox damage trigger checks

[toxicity188]

Motivation

• Remove a redundant cancellation check because triggered() already encapsulates the cancellation state for hitbox damage events to make the damage gate simpler and less error-prone.

Description

• Replaced if (!event.call().triggered() || event.cancelled) with if (!event.call().triggered()) across NMS and Fabric hitbox damage paths to centralize cancellation semantics.
• Files updated: nms/v1_21_R1/.../HitBoxImpl.kt, nms/v1_21_R3/.../HitBoxImpl.kt, nms/v1_21_R4/.../HitBoxImpl.kt, nms/v1_21_R5/.../HitBoxImpl.kt, nms/v1_21_R6/.../HitBoxImpl.kt, nms/v1_21_R7/.../HitBoxImpl.kt, and platform/fabric/.../HitBoxEntityImpl.kt.
• No API signatures were changed and behavior is intended to remain equivalent given current ModelDamagedEvent.call().triggered() semantics.
• Commit created: 5429d46d.

Testing

• Ran repository searches with rg to verify there are no remaining event.cancelled checks in the affected hitbox damage paths and confirmed all replaced occurrences now use if (!event.call().triggered()); this check succeeded.
• Verified the modified lines by inspecting surrounding code snippets to ensure listener.damage(event) is invoked before the triggered() check; no automated compile or unit tests were run in this change.

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Codex Task