Update install.sh：Replace "command -v" with encapsulated functionality (#6035)

Replace "command -v" with encapsulated functionality

scripts/install.sh

@@ -356,12 +356,12 @@ if ! lsmod | grep -q nvidia || ! lsmod | grep -q nvidia_uvm; then
 fi
 
 # make sure the NVIDIA modules are loaded on boot with nvidia-persistenced
-if command -v nvidia-persistenced > /dev/null 2>&1; then
+if available nvidia-persistenced; then
     $SUDO touch /etc/modules-load.d/nvidia.conf
     MODULES="nvidia nvidia-uvm"
     for MODULE in $MODULES; do
         if ! grep -qxF "$MODULE" /etc/modules-load.d/nvidia.conf; then
-            echo "$MODULE" | sudo tee -a /etc/modules-load.d/nvidia.conf > /dev/null
+            echo "$MODULE" | $SUDO tee -a /etc/modules-load.d/nvidia.conf > /dev/null
         fi
     done
 fi