Clarify authz comments - #11028

control: job assigned to worker 01KZF1QA9GNF13EVB5QK0W31JD [factory aws, i-0fcfdb9e5baba5f87] (queued for 52 s)
...
task: starting task 0: "setup"
task: process exited: duration 4116 ms, exit code 0
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task: starting task 1: "rust-toolchain"
task: process exited: duration 16707 ms, exit code 0
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task: starting task 2: "authentication"
task: process exited: duration 15 ms, exit code 0
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task: starting task 3: "clone repository"
task: process exited: duration 11467 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 (335/335)
| 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 1.69s
| 
| real    13:57.108502840
| user    21:04.331643464
| sys      4:18.080007177
| trap        0.330020378
| tflt        0.598192994
| dflt        0.872858901
| kflt        0.005380979
| lock  1:26:12.598578335
| slp   1:40:11.979312283
| lat        56.463456275
| stop     3:59.896106973
task: process exited: duration 965791 ms, exit code 0
|W| found 0 output files