fix(storage): use remove_owner_index and clean up guardian votes in archive_will (#332)

[XueyuanPang-Google]

Summary

Fixes #332 by refactoring archive_will in contracts/will/src/storage.rs to:

1. Use remove_owner_index instead of an inline open-coded removal loop (which preserves ordering and extends TTL appropriately).
2. Clean up dangling guardian trigger and cancel votes via reset_guardian_votes and reset_guardian_cancel_votes.

Verification

Aligns archive_will with other lifecycle completion functions.

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Payout Address: 0x4DF12f27bEDC11EDEAfa6154A193C65a329388DE