Fixes for PHPStan

[mikadamczyk]

🎫 Issue	N/A

Description:

PHPStan complains because $contentTypeData is declared as a non-nullable property of FieldDefinitionData.
That means it will always exist, so isset() is redundant. $contentTypeDraft is also declared as non-nullable in ContentTypeData.
Using ?? null suggests it might be null, which conflicts with the type declaration.

For QA:

Documentation:

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud