fix(language-core): always report missing props on `<slot>`

[KazariEX]

fix #4979

[pkg-pr-new[bot]]

Open in Stackblitz

vue-component-meta

``` pnpm add https://pkg.pr.new/vuejs/language-tools/vue-component-meta@4982 ```

vue-component-type-helpers

``` pnpm add https://pkg.pr.new/vuejs/language-tools/vue-component-type-helpers@4982 ```

@vue/language-plugin-pug

``` pnpm add https://pkg.pr.new/vuejs/language-tools/@vue/language-plugin-pug@4982 ```

@vue/language-core

``` pnpm add https://pkg.pr.new/vuejs/language-tools/@vue/language-core@4982 ```

@vue/language-server

``` pnpm add https://pkg.pr.new/vuejs/language-tools/@vue/language-server@4982 ```

@vue/language-service

``` pnpm add https://pkg.pr.new/vuejs/language-tools/@vue/language-service@4982 ```

vue-tsc

``` pnpm add https://pkg.pr.new/vuejs/language-tools/vue-tsc@4982 ```

@vue/typescript-plugin

``` pnpm add https://pkg.pr.new/vuejs/language-tools/@vue/typescript-plugin@4982 ```

commit: 66e58c3