Fixed exceptions in C# SDK when someone disconnects or when a transaction originates from CLI

crates/cli/src/subcommands/generate/csharp.rs

@@ -712,6 +712,8 @@ pub fn autogen_csharp_globals(items: &[GenItem], namespace: &str) -> Vec<(String
                     );
                 }
                 writeln!(output, "\"<none>\" => null,");
+                writeln!(output, "\"__identity_disconnected__\" => null,");
+                writeln!(output, "\"\" => null,"); //Transaction from CLI command
                 writeln!(
                     output,
                     r#"var reducer => throw new ArgumentOutOfRangeException("Reducer", $"Unknown reducer {{reducer}}")"#

crates/cli/tests/snapshots/codegen__codegen_csharp.snap

@@ -738,6 +738,8 @@ namespace SpacetimeDB
 				"repeating_test" => BSATNHelpers.FromProtoBytes<RepeatingTestArgsStruct>(argBytes),
 				"test" => BSATNHelpers.FromProtoBytes<TestArgsStruct>(argBytes),
 				"<none>" => null,
+				"__identity_disconnected__" => null,
+				"" => null,
 				var reducer => throw new ArgumentOutOfRangeException("Reducer", $"Unknown reducer {reducer}")
 			};
 			return new ReducerEvent(dbEvent, args);