class:name={ true } in combination with spread arguments is deleted on update

[cvlab]

Describe the bug
class:name={ true } in combination with spread arguments is deleted on spread arguments update

To Reproduce
REPL https://svelte.dev/repl/ff608fce63184816a57bbb5ae0ea7bd3?version=3.8.1

Additional context

<h1 class="cls" class:red={ true } { ...{ style } }>

update function is

p(changed, ctx) {
	set_attributes(h1, get_spread_update(h1_levels, [
		{ class: "cls svelte-kwtnbw" },
		(changed.style) && { style: ctx.style }
	]));
},

Because get_spread_update change class attribute and there is no toggle class call for red class, red class is deleted. Good solution is to compile truthy values of class:name={truthy} like static.