fix(reactivity): fix shallowReactive map "unwraps" the nested refs

[Alfred-Skyblue]

fixed #8501

I found inconsistent behavior with Map.set in #8501, this is a breaking change, please close this PR if this is intentional

[phonty29]

nice !

[pikax]

linking #8503 because it fix the same issue

[github-actions]

Size Report

Bundles

File	Size	Gzip	Brotli
runtime-dom.global.prod.js	87.1 kB (+18 B)	33.1 kB (+7 B)	29.9 kB (-3 B)
vue.global.prod.js	133 kB (+18 B)	50 kB (+7 B)	44.8 kB (+65 B)

Usages

Name	Size	Gzip	Brotli
createApp	48.4 kB (+18 B)	19 kB (+4 B)	17.4 kB (-50 B)
createSSRApp	51.6 kB (+18 B)	20.3 kB (+5 B)	18.5 kB (+1 B)
defineCustomElement	50.8 kB (+18 B)	19.8 kB (+5 B)	18.1 kB (-51 B)
overall	61.7 kB (+18 B)	23.9 kB (+4 B)	21.7 kB (+13 B)

[codspeed-hq]

CodSpeed Performance Report

Merging #8502 will degrade performances by 42.36%

_{Comparing Alfred-Skyblue:fix-shallowReactive (baaf820) with main (9fa8241)}

Summary

❌ 3 regressions
✅ 50 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	main	Alfred-Skyblue:fix-shallowReactive	Change
❌	write reactive map, don't read computed (never invoked)	62.2 µs	70.1 µs	-11.37%
❌	write reactive map property	85.8 µs	100.8 µs	-14.86%
❌	write reactive map, don't read 1000 computeds (never invoked)	76.7 µs	133 µs	-42.36%

[skirtles-code]

In my opinion, the changes proposed here are incorrect. The test expectations should not need to change for reactive() collections.

I think the fix proposed in #8503 is closer to the desired behaviour.