refactor(ap-change): remove unused tracking payload and redundant clones

[Perekup1]

This PR removes strictly redundant code paths in AP change computation without changing behavior.
Removed unused payload from ApTrackingBase::EnableStatement.

• Replaced .cloned() with .copied() for Option<usize> values fetched from maps.
• Simplified ApChangeCalcHelper::new to return Self instead of Result<Self, ApChangeError>.
• Updated calc_ap_changes call site to match the constructor signature.

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[reviewable-StarkWare]

This change is 

[orizi]

@orizi made 1 comment.
Reviewable status: 0 of 1 files reviewed, 1 unresolved discussion (waiting on Perekup1).

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crates/cairo-lang-sierra-ap-change/src/compute.rs line 37 at r1 (raw file):

enum ApTrackingBase {
    FunctionStart(FunctionId),
    EnableStatement,

there on purpose - revert.