fix(schema): avoid creating unnecessary clone of schematype in nested array so nested document arrays use correct constructor

[vkarpov15]

Fix #14101

Summary

The underlying issue in #14101 is that we have two different schema types for options and options.$, even though they should be the same. Which leads to issues when validating a subdoc of options.$'s caster using options schematype. Specifically triggering this if statement, which leads to issues with nested arrays because scope can be an array.

The fix is to avoid cloning, so options and options.$ are largely interchangeable as far as casting and validation are concerned.

Examples