fix: allow await in if block consequent and alternate

[yuki0418]

Closes #16885

Description

Check has_await in consequent and alternate as well.

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Latest commit: 1f639d5

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Playground

pnpm add https://pkg.pr.new/svelte@16890

[yuki0418]

From my understanding, node.metadata.expression.has_await checks {#if await Promise.resolve(true)}.

So it doesn't return true when only consequent or alternate have await operator.