falsy attachments don't work when passed as a prop

[jjones315]

Describe the bug

When trying to conditionally attach to a component when the attachment expression is false a run time error occurs.
for example

<Child1 {@attach enabled && attachment}>
</Child1>

will result in the error
TypeError: (get(...) && attachment) is not a function

while passing enabled down and putting the attachment expression in the Child component works as expected.

Reproduction

https://svelte.dev/playground/08d0da19e5204af9ba1d3103af029d69?version=5.33.4

click the "Enabled" checkbox to disable the attachment. notice the error. comment out <Child1... and <Child2... works as expected

Logs

Uncaught TypeError: (get(...) && attachment) is not a function

	in Child1.svelte
	in App.svelte

    at [@attach] (playground:output:3957:69)
    at eval (playground:output:3184:63)
    at update_reaction (playground:output:1949:57)
    at update_effect (playground:output:2115:19)
    at flush_queued_effects (playground:output:2230:7)
    at flush_queued_root_effects (playground:output:2201:6)

System Info

running in repl@5.33.4. don't have access to my machine atm

Severity

annoyance