Change DropdownField selectedOptions to not replace null value with default

To allow null values in sort options to not be first in list.

Author: antonnyst

src/js/components/Fields/DropdownField.js

@@ -91,7 +91,7 @@ export default class DropdownField extends React.Component {
 
     if (optionsProp) {
       // Value not set, default to first option
-      if (value === null || value === undefined) {
+      if (value === undefined) {
         selectedOptions = [optionsProp[0]];
       } else if (this.isMultiSelect()) {
         for (const multiSelectValue of value) {
@@ -174,7 +174,7 @@ export default class DropdownField extends React.Component {
   <div
     className={`dropdown-field__options__item ${option.className ? option.className : ''}`}
     key={option.value}
-    onClick={(e) => this.handleChange(option.value, is_selected)}
+    onClick={(e) => this.handleChange(option.value, is_selected)}
   >
     {!no_status_icon && is_selected && selected_icon}
     {option.label}