[feat] Various input validation changes + fixes

* Keep invalid input in subsequent prompts
* Remove useless placeholder values
* Only set PROCS variable once
* Make input collection loops more consistent

setup/so-setup

@@ -461,6 +461,12 @@ if [[ $is_sensor && ! $is_eval ]]; then
 		whiptail_suricata_pins
 		collect_mtu
 	else
+		if [[ $is_node && $is_sensor && ! $is_eval ]]; then
+			PROCS=$(( lb_procs / 2 ))
+			if [ "$PROCS" -lt 1 ]; then PROCS=1; else PROCS=$PROCS; fi
+		else
+			PROCS=$lb_procs
+		fi
 		[[ $ZEEKVERSION == "ZEEK" ]] && collect_zeek
 		collect_suri
 	fi