`MEMLEAK` caused by `openchannel_update` by passing the wrong psbt after `openchannel_init``

[enaples]

Scenario

A channel is opened using low-level RPC openchannel_init and openchannel_update, but during the update the user pass the wrong psbt.

Reproduce issue

1. Prepare PSBT 1
2. Prepare PSBT 2 (possibly with different utxo)
3. Initiate openchannel_init with PSBT 1
4. Call openchannel_update with PSBT 2

Error in logs

lightningd-1 2026-03-19T15:05:39.741Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1: MEMLEAK: 0x103718d28
lightningd-1 2026-03-19T15:05:39.741Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:   label=struct wally_psbt
lightningd-1 2026-03-19T15:05:39.741Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:   alloc:
lightningd-1 2026-03-19T15:05:39.741Z DEBUG   connectd: REPLY WIRE_CONNECTD_DEV_MEMLEAK_REPLY with 0 fds
lightningd-1 2026-03-19T15:05:39.741Z DEBUG   gossipd: REPLY WIRE_GOSSIPD_DEV_MEMLEAK_REPLY with 0 fds
lightningd-1 2026-03-19T15:05:39.764Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:     common/utils.c:34 (tal_wally_start)
lightningd-1 2026-03-19T15:05:39.764Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:     bitcoin/psbt.c:1074 (psbt_set_version)
lightningd-1 2026-03-19T15:05:39.764Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:     bitcoin/psbt.c:942 (fromwire_wally_psbt)
lightningd-1 2026-03-19T15:05:39.764Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:     openingd/dualopend_wiregen.c:821 (fromwire_dualopend_psbt_updated)
lightningd-1 2026-03-19T15:05:39.765Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:     openingd/dualopend.c:1461 (fetch_psbt_changes)
lightningd-1 2026-03-19T15:05:39.765Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:     openingd/dualopend.c:1487 (send_next)
lightningd-1 2026-03-19T15:05:39.765Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:     openingd/dualopend.c:2097 (run_tx_interactive)
lightningd-1 2026-03-19T15:05:39.765Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:     openingd/dualopend.c:3342 (opener_start)
lightningd-1 2026-03-19T15:05:39.765Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:     openingd/dualopend.c:4126 (handle_master_in)
lightningd-1 2026-03-19T15:05:39.765Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:     openingd/dualopend.c:4538 (main)
lightningd-1 2026-03-19T15:05:39.765Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:   steal:
lightningd-1 2026-03-19T15:05:39.765Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:     openingd/dualopend.c:1498 (send_next)
lightningd-1 2026-03-19T15:05:39.765Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:     openingd/dualopend.c:2097 (run_tx_interactive)
lightningd-1 2026-03-19T15:05:39.765Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:     openingd/dualopend.c:3342 (opener_start)
lightningd-1 2026-03-19T15:05:39.765Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:     openingd/dualopend.c:4126 (handle_master_in)
lightningd-1 2026-03-19T15:05:39.765Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:     openingd/dualopend.c:4538 (main)
lightningd-1 2026-03-19T15:05:39.765Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:   parents:
lightningd-1 2026-03-19T15:05:39.765Z **BROKEN** 033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a-dualopend-chan#1:     struct tx_state