Prefer use of $request->integer(...) over string casting

[dmohns]

Brief summary of the change made

Litte find&replace clean up to prefer

$request->integer('per_page', 15);

over

(int) $request->input('per_page', 15);

Are there any other side effects of this change that we should be aware of?

Describe how you tested your changes?

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Please confirm you have completed any of the necessary steps below.

• Meaningful Pull Request title and description
• Changes tested as described above
• Added appropriate documentation for the change.
• Created GitHub issues for any relevant followup/future enhancements if appropriate.

[beesaferoot]

Looks good 👍🏾