fix(seed): Add default values to incompleted declarations (#16704)

Closes #16696

fix(seed): Fix undefined render

seed/challenges/03-front-end-libraries/react-and-redux.json

@@ -543,9 +543,7 @@
             "  }",
             "  render() {",
             "    // complete the return statement:",
-            "    return (",
-            "",
-            "    );",
+            "    return (null);",
             "  }",
             "};"
           ],

seed/challenges/03-front-end-libraries/react.json

@@ -2596,11 +2596,11 @@
             "  }",
             "  handleClick() {",
             "    this.setState({",
-            "      counter: // change code here",
+            "      counter: 0 // change code here",
             "    });",
             "  }",
             "  render() {",
-            "    let expression = // change code here",
+            "    let expression = null; // change code here",
             "    return (",
             "      <div>",
             "        <button onClick={this.handleClick}>Play Again</button>",
@@ -2743,7 +2743,7 @@
             "    });",
             "  }",
             "  render() {",
-            "    const items = // change code here",
+            "    const items = null; // change code here",
             "    return (",
             "      <div>",
             "        <textarea",
@@ -2807,7 +2807,7 @@
             "];",
             "",
             "function Frameworks() {",
-            "  const renderFrameworks = // change code here",
+            "  const renderFrameworks = null; // change code here",
             "  return (",
             "    <div>",
             "      <h1>Popular Front End JavaScript Frameworks</h1>",
@@ -2885,8 +2885,8 @@
             "    }",
             "  }",
             "  render() {",
-            "    const usersOnline = // change code here",
-            "    const renderOnline = // change code here",
+            "    const usersOnline = null; // change code here",
+            "    const renderOnline = null; // change code here",
             "    return (",
             "       <div>",
             "         <h1>Current Online Users:</h1>",

seed/challenges/03-front-end-libraries/redux.json

@@ -676,16 +676,16 @@
           "ext": "jsx",
           "name": "index",
           "contents": [
-            "const INCREMENT = // define a constant for increment action types",
-            "const DECREMENT = // define a constant for decrement action types",
+            "const INCREMENT = null; // define a constant for increment action types",
+            "const DECREMENT = null; // define a constant for decrement action types",
             "",
-            "const counterReducer = // define the counter reducer which will increment or decrement the state based on the action it receives",
+            "const counterReducer = null; // define the counter reducer which will increment or decrement the state based on the action it receives",
             "",
-            "const incAction = // define an action creator for incrementing",
+            "const incAction = null; // define an action creator for incrementing",
             "",
-            "const decAction = // define an action creator for decrementing",
+            "const decAction = null; // define an action creator for decrementing",
             "",
-            "const store = // define the Redux store here, passing in your reducers"
+            "const store = null; // define the Redux store here, passing in your reducers"
           ]
         }
       },