fix: board <select> update on board detach

When the previously selected board is not detected, unset the `<select>`
option.

Closes #2222

Signed-off-by: Akos Kitta <a.kitta@arduino.cc>

arduino-ide-extension/src/browser/dialogs/firmware-uploader/firmware-uploader-component.tsx

@@ -104,6 +104,7 @@ export const FirmwareUploaderComponent = ({
   const onItemSelect = React.useCallback(
     (item: BoardListItemWithBoard | null) => {
       if (!item) {
+        setSelectedItem(null);
         return;
       }
       const board = item.board;