fix: ensure unused sol deposit channels are closed (#5312)

* chore: fix closing of unused deposit channels

* chore: update changelog

---------

Co-authored-by: albert <allimos3@gmail.com>

CHANGELOG.md

@@ -2,6 +2,13 @@
 
 All notable changes included in each Chainflip release will be documented in this file.
 
+## [1.6.7] - 2024-09-25
+
+### Fixes
+
+- Add missing broker fees migration.
+- Close expired Solana channels.
+
 ## [1.6.6] - 2024-09-24
 
 ### Fixes

engine/src/witness/sol/sol_deposits.rs

@@ -85,10 +85,14 @@ where
 				.filter_map(move |(deposit_channel, amount)| {
 					let amount: SolAmount = amount.saturated_into(); // TODO: Change the DeltaBasedIngress to not use the Chains Amount type but
 												 // instead use u256 or u128 or some generic.
-					let (_, current_total_ingressed) =
+					let (deposit_details, current_total_ingressed) =
 						deposit_channels.get(deposit_channel.address()).unwrap();
 					if amount != current_total_ingressed.amount ||
-						slot < current_total_ingressed.block_number
+						slot < current_total_ingressed.block_number ||
+						// We avoid submitting an extrinsic if the amount is unchanged. However, the delta_based_ingress election won't close a
+						// channel until at least one ingress submission reaches consensus. To ensure this happens, we submit the amount on the
+						// first witnessed slot after the deposit channel's close block.
+						slot >= deposit_details.close_block
 					{
 						Some((
 							*deposit_channel.address(),