Change csharp_indent_labels from flush_left to one_less_than_current (dotnet#16983)

Author: ahsonkhan

.editorconfig

@@ -29,7 +29,7 @@ csharp_indent_block_contents = true
 csharp_indent_braces = false
 csharp_indent_case_contents = true
 csharp_indent_switch_labels = true
-csharp_indent_labels = flush_left
+csharp_indent_labels = one_less_than_current
 
 # avoid this. unless absolutely necessary
 dotnet_style_qualification_for_field = false:suggestion