refactor: Remove misleading `callback_id` from `register_callback()` test function #3655

Job	Run time
Bazel Build All Config Check	5m 43s
Bazel Build Fuzzers	2m 48s
Bazel Test All	16m 22s
Bazel Build Fuzzers AFL	2m 22s
Bazel Test Darwin x86-64	38m 11s
Python CI Tests	1m 37s
Build IC	21m 50s
Cargo Build Release Linux	10m 16s
Cargo Clippy Linux	4m 23s
Build Determinism (//publish/binaries:upload, release, build-ic/release, false)	33s
Build Determinism (//publish/canisters:upload, canisters, build-ic/canisters, false)	23s
Build Determinism (//ic-os/guestos/envs/prod:upload_disk-img, guest-os/update-img, build-ic/icos/...	19s
Build Determinism (//ic-os/hostos/envs/prod:upload_update-img, host-os/update-img, build-ic/icos/...	20s
Build Determinism (//ic-os/setupos/envs/prod:upload_disk-img, setup-os/disk-img, build-ic/icos/se...	19s
	1h 45m 26s

Provide feedback