Drop settlement_call_data table (#2968)

# Description
Since we don't need to store then uninternalised and internalised
calldata, so the table `settlement_call_data` can be dropped.

PR rebased on top of #2964
as a continuation of it.

# Changes
- Drop the table `settlement_call_data`

## How to test
1. Regression tests

## Related Issues
Fixes #2939

---------

Co-authored-by: Martin Magnus <[email protected]>

crates/database/src/lib.rs

@@ -15,7 +15,6 @@ pub mod order_execution;
 pub mod order_history;
 pub mod orders;
 pub mod quotes;
-pub mod settlement_call_data;
 pub mod settlement_observations;
 pub mod settlement_scores;
 pub mod settlements;

database/README.md

@@ -343,19 +343,6 @@ Stores the best and second best solution quality (score) of every auction promis
 Indexes:
 - PRIMARY KEY: btree(`auction_id`)
 
-### settlement\_call\_data
-
-Stores the final calldata and uninternalized calldata of the winning solution for each auction
-
- Column                       | Type     | Nullable | Details
-------------------------------|----------|----------|--------
- auction\_id                  | bigint   | not null | id of the auction the winning transaction calldata belongs to
- call_data                    | bytea    | not null | final calldata as it appears on the blockchain
- uninternalized\_call\_data   | numeric  | not null | uninternalized calldata, different from final calldata if solution contains interactions that can be internalized against gpv2 settlement contract internal buffers.
-
-Indexes:
-- PRIMARY KEY: btree(`auction_id`)
-
 ### settlements
 
 Stores data and metadata of [`Settlement`](https://github.com/cowprotocol/contracts/blob/main/src/contracts/GPv2Settlement.sol#L67-L68) events emitted from the settlement contract.

database/sql/V071__drop_settlement_call_data.sql

@@ -0,0 +1,5 @@
+--- We don't need to store the uninternalised and internalised calldata, so this table can be dropped
+--- This is because we don't need to show/return the calldata from the competition endpoints for safety reasons
+--- The calldata can be recovered using any full node given the transaction hash which is later recovered when observing the settlement
+--- See more: https://github.com/cowprotocol/services/issues/2942
+DROP TABLE settlement_call_data;