Cleanup access to undefined properties in FieldType classes

Problem/Motivation

📌 Fix all code validate jobs running in GitLab CI Fixed is trying to get us to a fully clean set of passing code quality tests. There were a few PHPStan errors that were easier to silence and punt than fix:

 ------ -------------------------------------------------------------------------- 
  Line   src/Plugin/Field/FieldType/AddressItem.php                                
 ------ -------------------------------------------------------------------------- 
  357    Access to an undefined property                                           
         Drupal\address\Plugin\Field\FieldType\AddressItem::$langcode.             
         💡 Learn more:                                                            
            https://phpstan.org/blog/solving-phpstan-access-to-undefined-property  
  421    Access to an undefined property                                           
         Drupal\address\Plugin\Field\FieldType\AddressItem::$country_code.         
         💡 Learn more:                                                            
            https://phpstan.org/blog/solving-phpstan-access-to-undefined-property  
  429    Access to an undefined property                                           
         Drupal\address\Plugin\Field\FieldType\AddressItem::$langcode.             
         💡 Learn more:                                                            
            https://phpstan.org/blog/solving-phpstan-access-to-undefined-property  
 ------ -------------------------------------------------------------------------- 
 ------ -------------------------------------------------------------------------- 
  Line   src/Plugin/Field/FieldType/ZoneItem.php                                   
 ------ -------------------------------------------------------------------------- 
  75     Access to an undefined property                                           
         Drupal\address\Plugin\Field\FieldType\ZoneItem::$value.                   
         💡 Learn more:                                                            
            https://phpstan.org/blog/solving-phpstan-access-to-undefined-property  
 ------ -------------------------------------------------------------------------- 

These are currently being ignored in phpstan-baseline.neon

Steps to reproduce

Proposed resolution

1. Fix these for real.
2. Remove them from phpstan-baseline.neon

Remaining tasks

User interface changes

API changes

Data model changes