fix: patch the getCheckboxState method in the new flyout (#7)

Author: gonfunko

src/lib/blocks.js

@@ -328,7 +328,7 @@ export default function (vm, useCatBlocks) {
         this.jsonInit(json);
     };
 
-    ScratchBlocks.VerticalFlyout.getCheckboxState = function (blockId) {
+    ScratchBlocks.CheckableContinuousFlyout.prototype.getCheckboxState = function (blockId) {
         const monitoredBlock = vm.runtime.monitorBlocks._blocks[blockId];
         return monitoredBlock ? monitoredBlock.isMonitored : false;
     };