Fix/annexes link to not provided documents

[tsubik]

Fixes annexes still being copied into the doc_not_provided history entry when a document is deleted, or expires from not required, and goes back to not provided.

• OperatorDocument#destroy disconnects annexes before update!, so create_history no longer copies them; both run in one transaction
• disconnect_annexes also resets the cached operator_document_annexes, so a list loaded earlier can't be copied into history
• Destroy spec reloads the document first; the stale cached association was hiding the bug
• New fix:annexes_not_provided_history rake task removes annex links from doc_not_provided history entries. Annexes carried over to later versions before the disconnect release (2026-01-09) are left as they are

Deploy notes

• Deploy first, then run bin/rails fix:annexes_not_provided_history (dry run), review the output and rerun with FOR_REAL=true.

JIRA: https://gfw.atlassian.net/browse/OPEN-418

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