[Fix] Fixes inconsistency of nullability of schemas of properties that are a collection of structured types

[irvinesunday]

Fixes #467

This PR:

• Ensures that schemas of properties of collection of complex types are consistent with those of entity types, such that:

identities:
  type: array
  items:
    anyOf:
      - $ref: '#/components/schemas/microsoft.graph.objectIdentity'
      - type: object
         nullable: true

should be...

identities:
  type: array
  items:
    $ref: '#/components/schemas/microsoft.graph.objectIdentity'

[NB] Collection of structured types are not nullable.

• Updates tests
• Updates release notes

[sonarqubecloud]

Quality Gate passed

Kudos, no new issues were introduced!

0 New issues
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[baywet]

Marvelous!