Support nested unions when parsing FormData

[fehnomenal]

I have a schema that looks roughly like this

const weekDaySchema = z.enum(['mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun']);

const timeSpanSchema = z.object({ from: timeSchema, to: timeSchema });

const weekSchema = z.record(weekDaySchema, z.union([z.literal('default'), z.array(timeSpanSchema)]));

This nested union was not supported for parsing FormData entries.

This PR fixes this use case by trying each union option until the first succeeds or throws an error describing the failed types.

I'm not sure if this breaks anything else. Tests pass and I didn't notice anything off.

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Name	Status	Preview	Comments	Updated (UTC)
superforms	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	May 15, 2024 8:52am

[fehnomenal]

I noticed it does not work correctly when the union is at the top-level of an object. Working on it.

[fehnomenal]

This works now, if the union or exactly on of its options has a default value.

[ciscoheat]

Thank you, but I'm not sure when this will be used, since your schema contains nested data and that should not be handled by the form data parser?

If you still think it's needed, can you add some test cases as well, so I get a better idea of what's happening? :)