fix(types/ref): correct type inference for nested refs

[jh-leong]

close #11532

[github-actions]

Size Report

Bundles

File	Size	Gzip	Brotli
runtime-dom.global.prod.js	90.1 kB	34.6 kB	31.1 kB
vue.global.prod.js	147 kB	54 kB	48.1 kB

Usages

Name	Size	Gzip	Brotli
createApp	49.6 kB	19.5 kB	17.8 kB
createSSRApp	53.2 kB	21 kB	19.1 kB
defineCustomElement	51.9 kB	20.2 kB	18.5 kB
overall	63.1 kB	24.5 kB	22.3 kB

[jh-leong]

/ecosystem-ci run

[vue-bot]

📝 Ran ecosystem CI: Open

suite	result	latest scheduled
language-tools	❌ failure	❌ failure
nuxt	❌ failure	❌ failure
pinia	✅ success	✅ success
primevue	✅ success	✅ success
quasar	✅ success	✅ success
radix-vue	✅ success	✅ success
router	✅ success	✅ success
test-utils	✅ success	✅ success
vant	✅ success	✅ success
vite-plugin-vue	✅ success	✅ success
vitepress	✅ success	✅ success
vue-i18n	✅ success	✅ success
vue-macros	✅ success	❌ failure
vuetify	✅ success	✅ success
vueuse	❌ failure	✅ success
vue-simple-compiler	✅ success	✅ success

[jh-leong]

/ecosystem-ci run

[vue-bot]

📝 Ran ecosystem CI: Open

suite	result	latest scheduled
language-tools	❌ failure	❌ failure
nuxt	❌ failure	❌ failure
pinia	✅ success	✅ success
primevue	✅ success	✅ success
quasar	✅ success	✅ success
radix-vue	✅ success	✅ success
router	✅ success	✅ success
test-utils	✅ success	✅ success
vant	✅ success	✅ success
vite-plugin-vue	✅ success	✅ success
vitepress	✅ success	✅ success
vue-i18n	✅ success	✅ success
vue-macros	✅ success	❌ failure
vuetify	✅ success	✅ success
vueuse	✅ success	✅ success
vue-simple-compiler	✅ success	✅ success

[Alfred-Skyblue]

Sorry, I didn't notice that you already submitted a PR. I just created #11537. I found that in your PR, you modified the type, but the issue causing #11532 is because when we set a value to a ref, it leads to this._value = ref(xxx), and we didn't unwrap it in the getter. So, this caused the problem in #11532.

[yyx990803]

It's better to align the types with existing runtime behavior, since changing runtime behavior is actually breaking.