types(defineComponent): fix optional Boolean prop types (#2401)

fix #2338

test-dts/h.test-d.ts

@@ -198,3 +198,29 @@ describe('component w/ props w/ default value', () => {
 
   h(MyComponent, {})
 })
+
+// #2338
+describe('Boolean prop implicit false', () => {
+  const MyComponent = defineComponent({
+    props: {
+      visible: Boolean
+    }
+  })
+
+  h(MyComponent, {})
+
+  const RequiredComponent = defineComponent({
+    props: {
+      visible: {
+        type: Boolean,
+        required: true
+      }
+    }
+  })
+
+  h(RequiredComponent, {
+    visible: true
+  })
+  // @ts-expect-error
+  expectError(h(RequiredComponent, {}))
+})