fix: failed to fetch satisfactory slot (#533)

## Description

Moving that target slot call outside the loop to reduce the
FailedToFetchSatisfactorySlot probability compared to recomputing it on
every retry, because it removes the “moving target” that can keep
outrunning a lagging HTTP node.

Author: GabrielePicco

magicblock-account-cloner/src/remote_account_cloner_worker.rs

@@ -508,10 +508,10 @@ where
 
             // Fetch the account, repeat and retry until we have a satisfactory response
             let mut fetch_count = 0;
+            let min_context_slot =
+                self.account_updates.get_last_known_update_slot(&clock::ID);
             loop {
                 fetch_count += 1;
-                let min_context_slot =
-                    self.account_updates.get_last_known_update_slot(&clock::ID);
                 match self
                     .fetch_account_chain_snapshot(pubkey, min_context_slot)
                     .await