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.

IMPORTANT: Currently, changes must be backported to the in-proc branch to be included in Core Tools and non-Flex deployments.

Backport PR

[Copilot]

Pull Request Overview

This PR updates the .editorconfig file to standardize encoding and indentation settings across the project by adding global configuration options and reorganizing the file structure.

• Added global charset setting (utf-8) for all files
• Added global indent_style setting (space) for all files
• Moved C# specific rules under a dedicated [*.cs] section

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