refactor: Disable unused special members functions in UnlockContext

src/qt/walletmodel.cpp

@@ -477,13 +477,6 @@ WalletModel::UnlockContext::~UnlockContext()
     }
 }
 
-void WalletModel::UnlockContext::CopyFrom(UnlockContext&& rhs)
-{
-    // Transfer context; old object no longer relocks wallet
-    *this = rhs;
-    rhs.relock = false;
-}
-
 bool WalletModel::bumpFee(uint256 hash, uint256& new_hash)
 {
     CCoinControl coin_control;