Integrate Schema API into v2 Client

[oleksandrpravosudko-okta]

OKTA-453800, OKTA-453801

• add v3 Schema API
• use interface for models:
  • no emitted JS code for non-enums
  • remove instanceof assertions in integration tests

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Adding Tests
• Build related changes
• CI related changes
• Documentation changes
• Other... Please describe:

What is the current behavior?

Issue Number: N/A

What is the new behavior?

Does this PR introduce a breaking change?

• Yes
• No

Other information

Reviewers