feat(verify): strict verify iface status is pending

[ANISH-SR]

Summary of Changes

• Added a status guard to allow rejection only when iface.status == Pending.
• Returns DoubleZeroError::InvalidStatus for all other states.
• If the interface is Pending, the existing flow remains unchanged:
  • Set status to Rejected.
  • Write updated interface back to the device account.
• No other logic or account checks were modified.

Testing Verification

• All rust checks green.
• All linting checks green.

Closes #2231

[karl-dz]

Hi @ANISH-SR sorry for only getting to this PR until now.

Would you be able to add a simple test to verify that this check works? Thank you