Cast form status fields to integer to avoid haven error

[ezraporter]

Description

This PR implements the fix described in #232 (comment) to cast form_status_complete fields to integer to avoid failures when raw_or_label = "haven" and the REDCap project returns data from the API where an entire *_complete column is NA.

#234 describes an instance in which this can occur. We were already assuming these fields were integer type when applying factor levels so this change just ensures that explicitly.

Proposed Changes

List changes below in bullet format:

• Cast *_complete variables to integer in multi_choice_to_labels()
• Add test case to ensure that multi_choice_to_labels() succeeds when raw_or_label = "haven" and the data contains a *_complete variable that is fully NA

Issue Addressed

closes #232

PR Checklist

Before submitting this PR, please check and verify below that the submission meets the below criteria:

• New/revised functions have associated tests
• New/revised functions that update downstream outputs have associated static testing files (.RDS) updated under inst/testdata/create_test_data.R
• New/revised functions use appropriate naming conventions
• New/revised functions don't repeat code
• Code changes are less than 250 lines total
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• The appropriate developers are assigned to the PR
• Pre-release package version incremented using usethis::use_version()

Code Review

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Code Review Checklist

• I checked that new files follow naming conventions and are in the right place
• I checked that documentation is complete, clear, and without typos
• I added/edited comments to explain "why" not "how"
• I checked that all new variable and function names follow naming conventions
• I checked that new tests have been written for key business logic and/or bugs that this PR fixes
• I checked that new tests address important edge cases