ui: edit modals should use YAML option from API get endpoints

[hiddeco]

Edit modals like the one for Stages should use the YAML option from the respective get endpoint. Without it, the update they will issue will lack GVK information about the object. Which causes the operation to fail with an error like:

parse manifest: error unmarshaling manifest: error unmarshaling JSON: while decoding JSON: Object 'Kind' is missing in ''

An example of where this is being done correctly is

kargo/ui/src/features/stage/analysis-run-modal.tsx

Lines 17 to 21 in 595e4d0

	const { data, isLoading } = useQuery(getAnalysisRun, {
	namespace: projectName,
	name,
	format: RawFormat.YAML
	});

[hiddeco]

Already addressed by #1898.