fix(query): avoid executing transforms if query wasn't executed

[vkarpov15]

Fix #13165

Summary

Some of the refactoring we did to switch exec() to async/await created a quirk where we still execute query transforms even if the query errored out. This leads to odd consequences like throwing a DocumentNotFoundError if findOne() throws a cast error, even though Mongoose didn't execute a query.

Examples

[AbdelrahmanHafez]

Is there any way we can write a test to prevent a regression in the future?

[AbdelrahmanHafez]

LGTM, thanks! 👍