Reset next update time for failed orders on reload.

[bavshin-f5]

Some failures can be addressed by a configuration change, so we need to reschedule updates for the inherited failed orders after reload.

[Copilot]

Pull Request Overview

This PR addresses a bug where failed certificate orders maintain their next update time after a reload, preventing proper rescheduling. The fix ensures that pending certificates get their next update time reset to the default value during cloning operations.

• Reset next update time for pending certificates to allow immediate rescheduling
• Maintain existing next update time for ready certificates
• Refactor state assignment to handle both state and next update time together

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