fix: adjusted accordion trigger children so that asChild is working correctly

[domudev]

• Using asChild on AccordionTrigger previously caused an error: "React.Children.only expected to receive a single React element child." This happened because AccordionPrimitive.Trigger had two children, which triggered the error when asChild was used.
• The issue is now resolved by ensuring there is only one child node. This single child node is used internally, making both approaches compatible.
• The rotation and display of the chevron are now coupled to the asChild usage, and it works only for the predefined chevron.

[vercel]

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