fix(island-ui): Only set SelectController placeholder for undefined o…

…r null values (#16512)

* Fix: Only set placeholder for undefined or null

* conditional only for null

---------

Co-authored-by: hfhelgason <hfhelgason@deloitte.is>

libs/shared/form-fields/src/lib/SelectController/SelectController.tsx

@@ -57,7 +57,7 @@ export const SelectController = <Value, IsMulti extends boolean = false>({
   }
 
   const getValue = (value: Value | Value[]) => {
-    if (!value) {
+    if (value === null) {
       return null
     }