Add chip tool Darwin description to classes. (#18909)

* Add descriptions to structures, classes and event.

* Generated code

src/darwin/Framework/CHIP/templates/CHIPCommandPayloadsObjc-src.zapt

@@ -18,6 +18,13 @@ NS_ASSUME_NONNULL_BEGIN
   }
   return self;
 }
+
+- (NSString *)description
+{
+  NSString *descriptionString = [NSString stringWithFormat:@"<%@: {{#zcl_command_arguments}}{{asStructPropertyName label}}:%@; {{/zcl_command_arguments}}>", NSStringFromClass([self class]) {{#zcl_command_arguments}},{{#if isArray}}_{{asStructPropertyName label}}{{else if (isOctetString type)}}[_{{asStructPropertyName label}} base64EncodedStringWithOptions:0]{{else}}_{{asStructPropertyName label}}{{/if}}{{/zcl_command_arguments}}];
+  return descriptionString;
+}
+
 @end
 {{/zcl_commands}}
 {{/zcl_clusters}}

src/darwin/Framework/CHIP/templates/CHIPStructsObjc-src.zapt

@@ -16,6 +16,13 @@ NS_ASSUME_NONNULL_BEGIN
   }
   return self;
 }
+
+- (NSString *)description
+{
+  NSString *descriptionString = [NSString stringWithFormat:@"<%@: {{#zcl_struct_items}}{{asStructPropertyName label}}:%@; {{/zcl_struct_items}}>", NSStringFromClass([self class]){{#zcl_struct_items}},{{#if isArray}}_{{asStructPropertyName label}}{{else if (isOctetString type)}}[_{{asStructPropertyName label}} base64EncodedStringWithOptions:0]{{else}}_{{asStructPropertyName label}}{{/if}}{{/zcl_struct_items}}];
+  return descriptionString;
+}
+
 @end
 
 {{/zcl_structs}}
@@ -31,6 +38,13 @@ NS_ASSUME_NONNULL_BEGIN
   }
   return self;
 }
+
+- (NSString *)description
+{
+  NSString *descriptionString = [NSString stringWithFormat:@"<%@: {{#zcl_event_fields}}{{asStructPropertyName name}}:%@; {{/zcl_event_fields}}>", NSStringFromClass([self class]){{#zcl_event_fields}},{{#if isArray}}_{{asStructPropertyName name}}{{else if (isOctetString type)}}[_{{asStructPropertyName label}} base64EncodedStringWithOptions:0]{{else}}_{{asStructPropertyName name}}{{/if}}{{/zcl_event_fields}}];
+  return descriptionString;
+}
+
 @end
 
 {{/zcl_events}}