fix: Add Child component and props to prop-p-is-null sample

This commit adds a new Child component and its props to the prop-p-is-null sample in the Svelte package. The Child component receives props using the spread operator and the props are passed as undefined. This change ensures that the Child component is properly rendered with the correct props.

Co-authored-by: Simon H <[email protected]>

Author: fsoft72

packages/svelte/tests/runtime-legacy/samples/prop-p-is-null/Child.svelte

@@ -0,0 +1,6 @@
+<script>
+	$: x = Object.keys($$restProps).length;
+	$: y = Object.keys($$props).length;
+</script>
+
+{x} {y}

packages/svelte/tests/runtime-legacy/samples/prop-p-is-null/input.svelte

@@ -0,0 +1,5 @@
+<script>
+	import Child from './Child.svelte'
+</script>
+
+<Child {...undefined} />

packages/svelte/tests/runtime-legacy/samples/prop-p-is-null/output.json

@@ -0,0 +1,135 @@
+{
+	"html": {
+		"type": "Fragment",
+		"start": 56,
+		"end": 80,
+		"children": [
+			{
+				"type": "Text",
+				"start": 54,
+				"end": 56,
+				"raw": "\n\n",
+				"data": "\n\n"
+			},
+			{
+				"type": "InlineComponent",
+				"start": 56,
+				"end": 80,
+				"name": "Child",
+				"attributes": [
+					{
+						"type": "Spread",
+						"start": 63,
+						"end": 77,
+						"expression": {
+							"type": "Identifier",
+							"start": 67,
+							"end": 76,
+							"loc": {
+								"start": {
+									"line": 5,
+									"column": 11
+								},
+								"end": {
+									"line": 5,
+									"column": 20
+								}
+							},
+							"name": "undefined"
+						}
+					}
+				],
+				"children": []
+			}
+		]
+	},
+	"instance": {
+		"type": "Script",
+		"start": 0,
+		"end": 54,
+		"context": "default",
+		"content": {
+			"type": "Program",
+			"start": 8,
+			"end": 45,
+			"loc": {
+				"start": {
+					"line": 1,
+					"column": 0
+				},
+				"end": {
+					"line": 3,
+					"column": 0
+				}
+			},
+			"body": [
+				{
+					"type": "ImportDeclaration",
+					"start": 10,
+					"end": 44,
+					"loc": {
+						"start": {
+							"line": 2,
+							"column": 1
+						},
+						"end": {
+							"line": 2,
+							"column": 35
+						}
+					},
+					"specifiers": [
+						{
+							"type": "ImportDefaultSpecifier",
+							"start": 17,
+							"end": 22,
+							"loc": {
+								"start": {
+									"line": 2,
+									"column": 8
+								},
+								"end": {
+									"line": 2,
+									"column": 13
+								}
+							},
+							"local": {
+								"type": "Identifier",
+								"start": 17,
+								"end": 22,
+								"loc": {
+									"start": {
+										"line": 2,
+										"column": 8
+									},
+									"end": {
+										"line": 2,
+										"column": 13
+									}
+								},
+								"name": "Child"
+							}
+						}
+					],
+					"source": {
+						"type": "Literal",
+						"start": 28,
+						"end": 44,
+						"loc": {
+							"start": {
+								"line": 2,
+								"column": 19
+							},
+							"end": {
+								"line": 2,
+								"column": 35
+							}
+						},
+						"value": "./Child.svelte",
+						"raw": "'./Child.svelte'"
+					}
+				}
+			],
+			"sourceType": "module"
+		}
+	}
+}