Fix: Set model fields as optional if they're not explicitly used for node/edge generation logic

[d3vzer0]

Description

Fixed a collection issue where specific Okta fields were expected/required by the Pydantic model. This change sets these fields to be optional if they're not used (yet) for node/edge creation.

Motivation and Context

This fixes the issues as described above.

Resolves: BED-8389

How Has This Been Tested?

• Ran collection, preprocessing an conversion for the Okta collector on both OktaPreview tenants. Compared the count of unique nodes/edges based on a collection dataset before this change and after this change. Additionally, verified if this matches with Okta's OpenAPI schema.

Screenshots (if appropriate):

Types of changes

• Chore (a change that does not modify the application functionality)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)