PR: Remove local editconfig

Author: yungshinlintw

sdk/contentunderstanding/Azure.AI.ContentUnderstanding/.gitignore

@@ -1,13 +1,10 @@
 # Local-only files and temporary scripts (not committed to git)
-__local_only/
+.local_only/
 
 # User-specific configuration files (never commit appsettings.json - they may contain secrets)
 **/appsettings.json
 !**/appsettings.json.sample
 
-# EditorConfig file (SDK-specific, not committed)
-.editorconfig
-
 # Sample output directories (generated by sample execution)
 **/sample_output/