Properly scale the random in SimpleRandomCollection

[SirYwell]

Overview

Fixes #2219

Description

SimpleRandomCollection always selected an entry in the range [0, 1). This is wrong however, as it has to scale to [0, total).
This problem likely wasn't discovered before because most uses of the random pattern make use of FastRandomCollection instead.

Submitter Checklist

• Make sure you are opening from a topic branch (/feature/fix/docs/ branch (right side)) and not your main branch.
• Ensure that the pull request title represents the desired changelog entry.
• New public fields and methods are annotated with @since TODO.
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