[omdb] refactor attached_subnet_manager status into a Display and snapshot it - #11552

control: job assigned to worker 01M5JDAWPCEWE33MMF5EWJWC1M [factory aws, i-0972a9c6bcd88e499] (queued for 55 s)
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task: starting task 0: "setup"
task: process exited: duration 4110 ms, exit code 0
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task: starting task 1: "rust-toolchain"
task: process exited: duration 17036 ms, exit code 0
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task: starting task 2: "authentication"
task: process exited: duration 32 ms, exit code 0
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task: starting task 3: "clone repository"
task: process exited: duration 20194 ms, exit code 0
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task: starting task 4: "build"
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| info: running `cargo check --bins` on zone-setup (371/371)
| warning: profile package spec `blake2b_simd` in profile `dev` did not match any packages
| warning: profile package spec `rust-argon2` in profile `dev` did not match any packages
|     Checking uzers v0.12.2
|     Checking zone-setup v0.1.0 (/work/oxidecomputer/omicron/zone-setup)
|     Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.51s
| 
| real    12:12.140568053
| user    19:14.322121232
| sys      4:06.169738207
| trap        0.334852311
| tflt        0.601364812
| dflt        0.701532386
| kflt        0.004183070
| lock    57:04.615270880
| slp   1:31:06.793788646
| lat        40.674309536
| stop     3:21.006705282
task: process exited: duration 877285 ms, exit code 0
|W| found 0 output files