Resolve the issue with recursive and nested Zod schemas

[ZijiaZhang]

• I understand that this repository is auto-generated and my pull request may not be merged

Changes being requested

• Resolve the issue with recursive and nested Zod schemas.
• Add test for recursive json schema
• Fix the test with nested schema
• Fix the issue that the 'definitions' in the defaultOptions are not reset between function executions.

Additional context & links

#978

[RobertCraigie]

Thanks so much @ZijiaZhang! I really appreciate it.

I merged your changes separately in #992 as I wanted to make a couple minor style changes.