Deprecate unused constant BYTES_TO_READ in FileUploadResource and TemporaryJsonapiFileFieldUploader

Problem/Motivation

Follow up from #3380345: Create an InputStreamFileWriter for writing the input stream to a file we should deprecate the duplicate constants BYTES_TO_READ in both FileUploadResource and TemporaryJsonapiFileFieldUploader.

Steps to reproduce

Proposed resolution

Merge request link

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet