system using only 8 of 10 U.2s on madrid BRM42220004

This was originally observed under #5111 (where this sled went through the "add sled" flow). But we also found that after a fresh install of Omicron that included BRM42220004 (without the "add sled" flow), the same issue happened and there were only 8 Crucible zones on it.

The errors are:

00:26:53.592Z ERRO SledAgent (StorageManager): Persistent error:not queueing disk
    disk_id = DiskIdentity { vendor: "1b96", serial: "A079E3F8", model: "WUS4C6432DSP3X3" }
    err = PooledDisk(BadPartitionLayout { path: "/devices/pci@ab,0/pci1de,fff9@1,2/pci1b96,0@0/blkdev@w0014EE81000BC440,0:wd,raw", why: "Expected 0 partitions, only saw 1" })
    file = sled-storage/src/manager.rs:472
00:26:54.179Z ERRO SledAgent (StorageManager): Persistent error:not queueing disk
    disk_id = DiskIdentity { vendor: "1b96", serial: "A079DE8D", model: "WUS4C6432DSP3X3" }
    err = PooledDisk(ZpoolCreate(CreateError { err: Execution(CommandFailure(CommandFailureInfo { command: "/usr/sbin/zpool create oxp_d6149e62-ae84-4209-b943-4053fb9a8713 /devices/pci@38,0/pci1de,fff9@1,2/pci1b96,0@0/blkdev@w0014EE81000BC129,0:a", status: ExitStatus(unix_wait_status(256)), stdout: "", stderr: "cannot open '/devices/pci@38,0/pci1de,fff9@1,2/pci1b96,0@0/blkdev@w0014EE81000BC129,0:a': No such device or address\\n" })) }))
    file = sled-storage/src/manager.rs:472
00:28:50.331Z ERRO SledAgent (StorageManager): Persistent error:not queueing disk
    disk_id = DiskIdentity { vendor: "1b96", serial: "A079DE8D", model: "WUS4C6432DSP3X3" }
    err = PooledDisk(ZpoolCreate(CreateError { err: Execution(CommandFailure(CommandFailureInfo { command: "/usr/sbin/zpool create oxp_6ad8e920-ad0c-4629-8208-19dbf938a354 /devices/pci@38,0/pci1de,fff9@1,2/pci1b96,0@0/blkdev@w0014EE81000BC129,0:a", status: ExitStatus(unix_wait_status(256)), stdout: "", stderr: "cannot open '/devices/pci@38,0/pci1de,fff9@1,2/pci1b96,0@0/blkdev@w0014EE81000BC129,0:a': No such device or address\\n" })) }))
    file = sled-storage/src/manager.rs:472
00:28:50.605Z ERRO SledAgent (StorageManager): Persistent error:not queueing disk
    disk_id = DiskIdentity { vendor: "1b96", serial: "A079E3F8", model: "WUS4C6432DSP3X3" }
    err = PooledDisk(BadPartitionLayout { path: "/devices/pci@ab,0/pci1de,fff9@1,2/pci1b96,0@0/blkdev@w0014EE81000BC440,0:wd,raw", why: "Expected 0 partitions, only saw 1" })
    file = sled-storage/src/manager.rs:472