Replace DurationChoices by JobIntervalChoices

[alehaa]

NetBox version

v4.2-beta1

Feature type

Change to existing functionality

Triage priority

I volunteer to perform this work (if approved)

Proposed functionality

During the implementation of #17716, I added the JobIntervalChoices to simplify job scheduling. At the time of writing this PR, I wasn't aware that there was already a DurationChoices in the extras module used by the script form.

I suggest replacing it with the new JobIntervalChoices and also integrating its missing choices for "12 hours" and "30 days".

Use case

Code deduplication and increasing maintainability.

Database changes

None.

External dependencies

DurationChoices has never been part of a public API, so I think there are no side effects.