test(types): add missing as const constraints

Author: yyx990803

test-dts/mount.d-test.ts

@@ -93,7 +93,7 @@ expectError(
 const AppWithArrayProps = {
   props: ['a'],
   template: ''
-}
+} as const
 
 // accept props - vm is properly typed
 expectType<string>(

test-dts/shallowMount.d-test.ts

@@ -67,7 +67,7 @@ expectError(
 const AppWithArrayProps = {
   props: ['a'],
   template: ''
-}
+} as const
 
 // accept props
 // vm is properly typed