Errors in stubs causing phpstan to fail in php8.4

[mroeling]

PHP8.4
PHPStan-Doctrine 2.0.2
PHPStan level 4

After resolving #644 (thanks for the quick response!) new fatal issues arose.

• MongoClassMetadataInfo.stub line 40
• ClassMetadataInfo.stub line 59
• ClassMetadata.stub line 20