fix: widen ownership upon property access if necessary

[dummdidumm]

In case of something like foo = bar.map(...), foo would have ownership of the array itself, while the individual items would have ownership of the component that created the proxy. That means if we later do foo[0].baz = 42, we could get a false-positive ownership violation, since the two proxies are not connected to each other via the parent relationship. For this reason, we need to widen the ownership of the children upon access when we detect they are not connected.

I'm a tiny bit worried about the potential overhead of this being invoked in a hot path (more likely with reads) but it should be fine since it only goes one level deep.

Fixes #13137

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