Stop error when exiting menus without making a selection.

linux-game-manager.sh

@@ -511,6 +511,10 @@ download_named() {
     # Required arguments: filename url
     # Only works with one file at a time.
     local dest="$1"
+    # Validate arguments
+    if [[ -z "$dest" ]] || [[ -z "$2" ]]; then
+        return 1
+    fi
     # Remove the destination file if it is empty.
     test -s "${cache}/${dest}" || rm -f "${cache}/${dest}" 2> /dev/null
     if [[ "${redownload}" == "true" ]] && [[ -e "${cache}/${dest}" ]]; then
@@ -613,6 +617,9 @@ game_installer() {
     # Show game selection dialog
     game="$(ui_menu "Game Installer" "Game Installer" "Please select a game to install" "${menuList[@]}")"
     # Handle selection
+    if [[ -z "$game" ]]; then
+        exit 0
+    fi
     if [[ -n "$game" ]]; then
         if [[ "$game" == "Donate" ]]; then
             open_url "https://ko-fi.com/stormux"