sled-agent: Remove direct dpd NAT entry creation in service zone startup path - #11073

control: job assigned to worker 01KZVV9PR1TVDRZQP3NTWQHV8A [factory aws, i-0abeeed6f7d1879c6] (queued for 48 s)
...
task: starting task 0: "setup"
task: process exited: duration 4167 ms, exit code 0
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task: starting task 1: "rust-toolchain"
task: process exited: duration 18896 ms, exit code 0
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task: starting task 2: "authentication"
task: process exited: duration 22 ms, exit code 0
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task: starting task 3: "clone repository"
task: process exited: duration 18658 ms, exit code 0
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task: starting task 4: "build"
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| a out/probe.tar.gz 3037K
| a out/propolis-server.tar.gz 34642K
| a out/pumpkind-gz.tar 26647K
| a out/switch-softnpu.tar.gz 499423K
| 
| real     1:29.561947921
| user     1:26.457822507
| sys         5.099622861
| trap        0.006812853
| tflt        0.000000000
| dflt        0.000000000
| kflt        0.000000000
| lock        0.000000000
| slp      1:26.343329198
| lat         1.211814811
| stop        0.000178990
task: process exited: duration 1235438 ms, exit code 0
|W| found 1 output files
|W| uploading: /work/package.tar.gz (2760283410 bytes)
|W| uploaded: /work/package.tar.gz