Check for starship to avoid errors with nushell config

dot_config/nushell/env.nu.tmpl

@@ -2,11 +2,13 @@
 #{{- /* vim: set filetype=nu: */ -}}
 # Nushell Environment Config File
 
+#{{ if lookPath "starship" -}}
 def command_prompt [] {(
     starship prompt
         $'--cmd-duration=($env.CMD_DURATION_MS)'
         $'--status=($env.LAST_EXIT_CODE)'
 )}
+#{{- end }}
 
 def add_xdg [name ...parts] {
     if $name in $env {
@@ -88,7 +90,9 @@ load-env {
         | uniq)
 
     PROMPT_COMMAND_RIGHT: ""
+    #{{ if lookPath "starship" -}}
     PROMPT_COMMAND: {|| command_prompt }
+    #{{- end }}
 
     PROMPT_INDICATOR: ""
     PROMPT_INDICATOR_VI_INSERT: ": "