fix: resolve infinite loop in _white_list_collection

apps/blockchain/starknet/src/bridge.cairo

@@ -540,6 +540,7 @@ mod bridge {
                         self.white_listed_list.write(prev, (active, target));
                         break;
                     }
+                    prev = next;
                 };
                 self.white_listed_list.write(collection, (false, no_value));
             }

apps/blockchain/starknet/src/tests/bridge_t.cairo

@@ -831,6 +831,102 @@ mod tests {
 
     }
 
+    #[test]
+    fn admin_remove_whitelist_correctly() {
+        let erc721b_contract_class = declare("erc721_bridgeable");
+
+        let BRIDGE_ADMIN = starknet::contract_address_const::<'starklane'>();
+        let BRIDGE_L1 = EthAddress { address: 'starklane_l1' };
+
+        let bridge_address = deploy_starklane(BRIDGE_ADMIN, BRIDGE_L1, erc721b_contract_class.class_hash);
+        let bridge = IStarklaneDispatcher { contract_address: bridge_address };
+
+        let collection1 = starknet::contract_address_const::<'collection1'>();
+        let collection2 = starknet::contract_address_const::<'collection2'>();
+        let collection3 = starknet::contract_address_const::<'collection3'>();
+        let collection4 = starknet::contract_address_const::<'collection4'>();
+        let collection5 = starknet::contract_address_const::<'collection5'>();
+        start_prank(CheatTarget::One(bridge_address), BRIDGE_ADMIN);
+        bridge.enable_white_list(true);
+        stop_prank(CheatTarget::One(bridge_address));
+
+        /// add whitelists
+        let mut spy = spy_events(SpyOn::One(bridge_address));
+        start_prank(CheatTarget::One(bridge_address), BRIDGE_ADMIN);
+        bridge.white_list_collection(collection1, true);
+        bridge.white_list_collection(collection2, true);
+        bridge.white_list_collection(collection3, true);
+        bridge.white_list_collection(collection4, true);
+        bridge.white_list_collection(collection5, true);
+        stop_prank(CheatTarget::One(bridge_address));
+
+        spy.assert_emitted(@array![
+            (
+                bridge_address,
+                bridge::Event::CollectionWhiteListUpdated(
+                    bridge::CollectionWhiteListUpdated {
+                        collection: collection1,
+                        enabled: true,
+                    }
+                )
+            ),
+            (
+                bridge_address,
+                bridge::Event::CollectionWhiteListUpdated(
+                    bridge::CollectionWhiteListUpdated {
+                        collection: collection2,
+                        enabled: true,
+                    }
+                )
+            ),
+            (
+                bridge_address,
+                bridge::Event::CollectionWhiteListUpdated(
+                    bridge::CollectionWhiteListUpdated {
+                        collection: collection3,
+                        enabled: true,
+                    }
+                )
+            ),
+            (
+                bridge_address,
+                bridge::Event::CollectionWhiteListUpdated(
+                    bridge::CollectionWhiteListUpdated {
+                        collection: collection4,
+                        enabled: true,
+                    }
+                )
+            ),
+            (
+                bridge_address,
+                bridge::Event::CollectionWhiteListUpdated(
+                    bridge::CollectionWhiteListUpdated {
+                        collection: collection5,
+                        enabled: true,
+                    }
+                )
+            )
+        ]);
+
+        // now try to remove from whitelist collection 3.
+        // this tests the loop
+        start_prank(CheatTarget::One(bridge_address), BRIDGE_ADMIN);
+        bridge.white_list_collection(collection3, false);
+        stop_prank(CheatTarget::One(bridge_address));
+
+        spy.assert_emitted(@array![
+            (
+                bridge_address,
+                bridge::Event::CollectionWhiteListUpdated(
+                    bridge::CollectionWhiteListUpdated {
+                        collection: collection3,
+                        enabled: false,
+                    }
+                )
+            ),
+        ]);
+    }
+
     #[test]
     #[should_panic]
     fn deposit_token_not_enabled() {