Add schema wrapper argument to \Drupal\Core\Config\StorableConfigBase::castValue() and do not store it as a property on the config object

Problem/Motivation

#3535199: Saving untrusted config results in memory leak fixes a memory leak due to the \Drupal\Core\Config\StorableConfigBase::$schemaWrapper property. But we can refactor \Drupal\Core\Config\StorableConfigBase::castValue() so we don't need to store it as a property.

Proposed resolution

Add the schema wrapper as an argument to castValue() and do not store it as a property.

Remaining tasks

User interface changes

None

Introduced terminology

N/a

API changes

TBD

Data model changes

None

Release notes snippet

N/a