Backend: inputs:regex bug that can throw a 500

Summary

While investigating a behavior noted in #458935 (comment 2073899952), an inputs:regex bug was uncovered that can throw a HTTP 500 error.

Definition of Done

CI config validations were throwing a 500 when giving a non-string value to regex validation. This MR prevents that by returning early from the regex validation when the given value is not a string.

This fix will prevent a HTTP 500 error from occurring when using inputs:regex.

Details

Roles involved

• Design
• Technical Writing
• Backend
• Frontend
• Test engineering

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