Add force_close_spend_delay filed for ChannelClosure

[EthanYuan]

• Add force_close_spend_delay filed for ChannelClosure, a call to the list_channel_closures method will reflect this
• Add force_close_spend_delay filed for MutinyChannel, a call to the list_channels method will reflect this

force_close_spend_delay is set to None for older versions of the data.

/// Information about a channel that was closed.
#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq, Hash)]
#[wasm_bindgen]
pub struct ChannelClosure {
    channel_id: Option<String>,
    node_id: Option<String>,
    reason: String,
    pub timestamp: u64,
    channel_funding_txo: Option<String>,
    force_close_spend_delay: Option<u16>,
}

#[derive(Serialize, Deserialize, Clone, Eq, PartialEq)]
#[wasm_bindgen]
pub struct MutinyChannel {
    user_chan_id: String,
    pub balance: u64,
    pub size: u64,
    pub reserve: u64,
    pub inbound: u64,
    outpoint: Option<String>,
    peer: String,
    pub confirmations_required: Option<u32>,
    pub confirmations: u32,
    pub is_outbound: bool,
    pub is_usable: bool,
    pub is_anchor: bool,
    pub force_close_spend_delay: Option<u16>,
}

The definition of force_close_spend_delay is as follows:

	/// The number of blocks (after our commitment transaction confirms) that we will need to wait
	/// until we can claim our funds after we force-close the channel. During this time our
	/// counterparty is allowed to punish us if we broadcasted a stale state. If our counterparty
	/// force-closes the channel and broadcasts a commitment transaction we do not have to wait any
	/// time to claim our non-HTLC-encumbered funds.
	///
	/// This value will be `None` for outbound channels until the counterparty accepts the channel.
	pub force_close_spend_delay: Option<u16>,

[EthanYuan]

When channel_closeure stored as a placeholder, it can be filtered out when list_channel_closures is called from the front end. @Flouse @ShookLyngs

[Flouse]

ok, i see