[12.x] Uncomment $offset param type in QueryPluginBase::setOffset

Problem/Motivation

Followup for 🐛 An empty views pager offset field can cause a PHP type error to be triggered. Needs work to add strict typing to QueryPluginBase::setOffset which is currently commented out as per https://www.drupal.org/about/core/policies/core-change-policies/how-to-d... →

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet