fix: TypeScript sample raises type error (#2376)

Author: hletrd

examples/sample-app-ts/src/index.ts

@@ -30,7 +30,7 @@ const ws = Blockly.inject(blocklyDiv, {toolbox});
 // generated code from the workspace, and evals the code.
 // In a real application, you probably shouldn't use `eval`.
 const runCode = () => {
-  const code = javascriptGenerator.workspaceToCode(ws);
+  const code = javascriptGenerator.workspaceToCode(ws as Blockly.Workspace);
   if (codeDiv) codeDiv.textContent = code;
 
   if (outputDiv) outputDiv.innerHTML = '';