Disable OmniSharp by default for C# files (#44427)

In preparation for https://github.com/zed-extensions/csharp/pull/11. Do
not merge before that PR is published.

Release Notes:

- Added support for Roslyn in C# files. Roslyn will now be the default
language server for C#
4106c8a188Finn Evers committed on 12/10/2025, 3:12:41 PM· committed by GitHubparent21f7e6a
1 file changedLine totals unavailable