Bug: `SimpleRng::next_u32` name is invalid

[PiotrKorkus]

Original report: https://github.com/qorix-group/inc_orchestrator_internal/issues/293

Describe the bug:

next_u32 returns u64.

Steps to reproduce the behavior:

N/A

Observed behavior:

next_u32 returns u64.

Expected behavior

Function should be renamed to next_u64, next, or some other name.

Occurrence:

N/A

Attachments / Logs: