enh: nw.Schema.from_native ?

[MarcoGorelli]

I'm wondering if we should allow nw.Schema.from_native. It would be kinda cool, and would allow you to convert any supported schema to say pyarrow schema

[dangotbanned]

Big +1 from me on adding .(from|to)_* pairs in more places throughout narwhals.

pyarrow is especially strict in forcing you to use their native containers 😒