fix(ipa): Separate the word-count validation for Operation IDs

[yelizhenden-mdb]

Proposed changes

Jira ticket: CLOUDP-368244

This PR separates operation ID length validation into dedicated rules, distinct from the existing operation ID validness validation. This allows for more granular control and clearer error messages when operation IDs exceed the recommended 4-word limit.

New operationID length validation rules:

• Validates that operation IDs don't exceed 4 words
• Requires x-xgen-operation-id-override extension for longer operation IDs
• Supports x-xgen-IPA-exception for documented exceptions

For PATCH /api/atlas/v2/orgs/{orgId}/invites/{invitationId} operation, we will need to:

• Remove the exception for valid-operation-id, and
• Add an exception for operation-id-length

Checklist

• I have signed the MongoDB CLA
• I have added tests that prove my fix is effective or that my feature works

Changes to Spectral

• I have read the README file for Spectral Updates

Further comments