Updating default file encoding configuration

[fabiocav]

This pull request makes a minor update to the .editorconfig file to standardize file encoding settings across the project. The main change is the addition of a charset = utf-8 (no BOM) setting for all files, replacing the previous utf-8-bom setting for code files.

I am not changing all files with this PR to avoid the churn and history mess. This will ensure the configuration is enforced as we continue to work on the repo. We can evaluate changes to other files if needed.

Pull request checklist

• My changes do not require documentation changes
  • Otherwise: Documentation issue linked to PR
• My changes do not need to be backported to a previous version
  • Otherwise: Backport tracked by issue/PR #11248
• My changes should not be added to the release notes for the next release
  • Otherwise: I've added my notes to release_notes.md
• I have added all required tests (Unit tests, E2E tests)