Restrict spreading for unknown Type with non object constraint

[collin5]

Fixes #30851

[collin5]

cc @orta

[orta]

Looks good - can you humor me and add one extra test here:

TypeScript/tests/baselines/reference/unknownType1.js

Lines 142 to 146 in b57b5fe

	function f26(x: {}, y: unknown, z: any) {
	let o1 = { a: 42, ...x }; // { a: number }
	let o2 = { a: 42, ...x, ...y }; // unknown
	let o3 = { a: 42, ...x, ...y, ...z }; // any
	}

Specifically for the any passing? e.g.

let o4 = { a: 42, ...z };

Then I'm happy to merge 👍

[collin5]

Done. Thank you.

[orta]

Thanks!