Make fixture update code more consistent

[pokey]

Use normalisation code for updating fixtures in

cursorless/src/test/suite/recorded.test.ts

Lines 130 to 138 in a4cee96

	const outputFixture = {
	...fixture,
	finalState: undefined,
	decorations: undefined,
	returnValue: undefined,
	thrownError: { name: error.name },
	};
	await fsp.writeFile(file, serialize(outputFixture));

, and other places we upgrade fixtures from the Update fixtures launch config

Factored out of todo item in description of #942