chore: Remove vestigial getrandom dependency

[github-actions[bot]]

Test flake analysis

status	platform	features	toolchain
🟡	ubuntu-latest	test-kubo,headers	stable
🟢	windows-latest	test-kubo,headers	stable
🟢	macos-13	test-kubo,headers,rocksdb	stable
🟢	macos-13	test-kubo,headers	stable
🟡	ubuntu-latest	test-kubo,headers	nightly
🟢	ubuntu-latest	test-kubo,headers,rocksdb	stable

Flake summary for ubuntu-latest, test-kubo,headers, stable

     Summary [  49.903s] 210 tests run: 210 passed (1 flaky), 2 skipped
   FLAKY 2/5 [   4.832s] noosphere::distributed_basic gateway_publishes_and_resolves_petnames_configured_by_the_client

Flake summary for ubuntu-latest, test-kubo,headers, nightly

     Summary [  68.071s] 210 tests run: 210 passed (1 flaky), 2 skipped
   FLAKY 2/5 [  26.370s] noosphere::distributed_stress multiplayer::orb_can_render_peers_in_the_sphere_address_book

[jsantell]

Handling in #850