@valibot/to-json-schema - add support for Async schemas

[hollandjake]

Add support for async schemas (v.BaseSchemaAsync<unknown, unknown, v.BaseIssue>) so that we can get the structure out of a schema (of course it cant run the async logic)

This should function similarly to the existing toJSONSchema

[fabian-hiller]

Hey, thank you for creating this issue. What is your use case?

[hollandjake]

@fabian-hiller I have an Async schema due to needing to run an checkAsync on a particular field in the object. this of course means the top level object also has to be objectAsync. Im aware the check wont be included inside the schema. but given I can exclude the action it should still be accepted as a valid schema

[fabian-hiller]

Make sense. Yes, I think we should support it for objectAsync but for checkAsync the users should configure errorMode, ignoreActions or overrideAction.