timer: removes NewSafeTimer in favor of time.After

[mismithhisler]

Description

This is a followup to #27784 where we removed the semgrep rule that prevented use of time.After because prior to Go 1.23, it was not garbage collected.

Testing & Reproduction steps

Links

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Changes to Security Controls

Are there any changes to security controls (access controls, encryption, logging) in this pull request? If so, explain.