Fix import error in CSharpLanguageServer

Fixed incorrect import path: changed from 'solidlsp.config' to 'solidlsp.ls_config'
to match the actual module structure used throughout the codebase.

src/solidlsp/language_servers/csharp_language_server/csharp_language_server.py

@@ -11,7 +11,7 @@ import threading
 
 from overrides import override
 
-from solidlsp.config import LanguageServerConfig
+from solidlsp.ls_config import LanguageServerConfig
 from solidlsp.exceptions import LanguageServerException
 from solidlsp.logger import LanguageServerLogger
 from solidlsp.ls import SolidLanguageServer