Fix "Schema Key" becoming an entry in the meditor

Pydantic 2.0's JSON schema export no longer specifies a `type` field for
the `schemaKey` property, and leaves it undefined instead. This change
makes it so an undefined type also delegates it as a "basic schema",
meaning it will not be rendered as its own tab in the meditor.

web/src/components/Meditor/types.ts

@@ -65,7 +65,7 @@ export const isJSONSchema = (schema: JSONSchemaUnionType): schema is JSONSchema7
 
 export const isBasicSchema = (schema: JSONSchemaUnionType): schema is BasicSchema => (
   isJSONSchema(schema)
-  && isBasicType(schema.type)
+  && (isBasicType(schema.type) || schema.type === undefined)
 );
 
 export const isObjectSchema = (schema: JSONSchemaUnionType): schema is ObjectSchema => (