Traceback on schedule creation

What does this MR do and why?

Concatenates interval variable to be of type int. It's currently a string due to it being pulled from a request argument. This was overlooked in the process of adding a sanity check.

That's what we get for implementing this on little sleep ;) sorry friends!

Linked Issues: #167 (closed)

Screenshots or screen recordings

How to set up and validate locally

Create a basic schedule with "days" interval.

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