Improve whiptail menu UI in install_script function

Updated the whiptail menu in the install_script function to enhance usability. Changes include adjusting the backtitle, adding --fb and --notags options, updating the menu prompt with navigation instructions, and increasing the menu width for better display.

misc/build.func

@@ -1537,13 +1537,16 @@ install_script() {
       menu_items+=("4" "Settings")
     fi
 
-    TMP_CHOICE=$(whiptail --backtitle "[dev] Proxmox VE Helper Scripts" \
+    TMP_CHOICE=$(whiptail \
+      --backtitle "Proxmox VE Helper Scripts" \
       --title "Community-Scripts Options" \
       --ok-button "Select" --cancel-button "Exit Script" \
-      --menu "Choose an option:" 20 40 9 \
+      --fb --notags \
+      --menu "\nChoose an option:\n\nUse TAB or Arrow keys to navigate, ENTER to select.\n" \
+      20 60 9 \
       "${menu_items[@]}" \
-      --default-item "1" 3>&1 1>&2 2>&3) || exit_script
-
+      --default-item "1" \
+      3>&1 1>&2 2>&3) || exit_script
     CHOICE="$TMP_CHOICE"
   fi