Fix dynamic child slot overriding

[TimDirks]

In the Dropdown.vue component we try to dynamically override the child's slots to pass them on to the parent. This works fine when served locally but when trying to make a build, rollup will give errors stating Type 'number' is not assignable to type 'Slot' for the Dropdown.vue component.

Same story for the FormDropdown.vue component. However, for that component rollup gives the error Type 'Function' is not assignable to type 'Slot'.

The issue is overriding the child's slots. Dynamically creating NEW slots in a component is fine for rollup.