Drop file_checksum column from Xray_reports table

What does this MR do and why?

This MR addresses #500462 (closed)

As a follow up to this issue: #479185 (closed), we are removing the xray_reports.file_checksum database column.

This MR drops the file_checksum column from the xray_reports table, following a multi-release approach for safe column removal.

ignore_column was added in this previous MR.

Migration:

bundle exec rails db:rollback:main VERSION=20241119105148

main: == 20241119105148 RemoveFileChecksumFromXrayReports: reverting ================
main: -- add_column(:xray_reports, :file_checksum, :binary, {:null=>true})
main:    -> 0.0075s
main: == 20241119105148 RemoveFileChecksumFromXrayReports: reverted (0.0114s) =======

bundle exec rails db:migrate

main: == 20241119105148 RemoveFileChecksumFromXrayReports: migrating ================
main: -- remove_column(:xray_reports, :file_checksum)
main:    -> 0.0024s
main: == 20241119105148 RemoveFileChecksumFromXrayReports: migrated (0.0058s) =======

Before	After

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.