Adjust ReadOnlySignal so we cant widen the type

[JoviDeCroock]

Avoid inheriting from signal in ReadonlySignal so we can't accidentally widen the type by doing const computed: Signal<any> = useComputed(() => {}), in widening this type we would lose the readonly aspect of the value property effectively making it a mutable signal.

Fixes https://github.com/preactjs/signals/issues/585

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Latest commit: 57ab3de3acdfb0f38705a979b9bfde09ce012c45

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| Name | Type | | -------------------- | ----- | | @preact/signals-core | Minor |

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Size Change: 0 B

Total Size: 83 kB

ℹ️ View Unchanged

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