Aria attribute aria-controls points element before it's available in DOM

Running an accesibility check on the component reveals that the aria-controls attribute of the searchbox points to a non-existing element id.

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I'm using this browser extension to check. Ran this check directly on https://vue-multiselect.js.org/

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The element does appear to exist here but because it's before under a v-if it will confuse screen readears and not work properly.

https://github.com/shentao/vue-multiselect/blob/343f18063d83dc2dea98b9f659c89c7246521d97/src/Multiselect.vue#L107