Add file upload lock handling to FileUploadHandler

Problem/Motivation

As part of #3221796: [META] Modernise file upload logic we identified that file locking occurs in 3 places:

• \Drupal\jsonapi\Controller\TemporaryJsonapiFileFieldUploader
• \Drupal\file\Plugin\rest\resource\FileUploadResource
• \Drupal\ckeditor5\Controller\CKEditor5ImageController

However, it doesn't occur in file_save_upload() which is currently the only code using FileUploadHandler.

Steps to reproduce

Proposed resolution

Add lock support to FileUploadHandler to make migrating those other services over easier.

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet