[Refactor♻️]Refactor BrokerHeartbeatRequestHeader with derive marco RequestHeaderCodec

[mxsm]

Which part of the code will be refactored?

Refactor example:

rocketmq-rust/rocketmq-remoting/src/protocol/header/message_operation_header/send_message_request_header.rs

Lines 29 to 63 in a720b7f

	#[derive(Debug, Clone, Serialize, Deserialize, Default, RequestHeaderCodec)]
	#[serde(rename_all = "camelCase")]
	pub struct SendMessageRequestHeader {
	#[required]
	pub producer_group: CheetahString,
	#[required]
	pub topic: CheetahString,
	#[required]
	pub default_topic: CheetahString,
	#[required]
	pub default_topic_queue_nums: i32,
	#[required]
	pub queue_id: Option<i32>,
	#[required]
	pub sys_flag: i32,
	#[required]
	pub born_timestamp: i64,
	#[required]
	pub flag: i32,
	pub properties: Option<CheetahString>,
	pub reconsume_times: Option<i32>,
	pub unit_mode: Option<bool>,
	pub batch: Option<bool>,
	pub max_reconsume_times: Option<i32>,
	#[serde(flatten)]
	pub topic_request_header: Option<TopicRequestHeader>,
	}

What problems does the refactor aim to solve?

No response

Do you have any specific design or implementation considerations?

No response

Is there a related issue or PR?

No response

Checklist

• Ensure the refactor does not introduce new bugs

• Update unit tests if applicable

• Ensure the refactor does not negatively impact performance

• Document any new patterns or architecture changes

• Test the refactor in different environments (e.g., staging, production)