refactor: unify command declaration across codebase

plugins/domains/subcommands/clear

@@ -6,10 +6,12 @@ source "$PLUGIN_AVAILABLE_PATH/domains/functions"
 
 cmd-domains-clear() {
   declare desc="clear all app domains"
-  local cmd="domains:clear"
-  [[ -z $2 ]] && dokku_log_fail "Please specify an app to run the command on"
-  verify_app_name "$2"
-  local APP="$2"
+  declare cmd="domains:clear"
+  [[ "$1" == "$cmd" ]] && shift 1
+  declare APP="$1"
+
+  [[ -z "$APP" ]] && dokku_log_fail "Please specify an app to run the command on"
+  verify_app_name "$APP"
   local APP_VHOST_PATH="$DOKKU_ROOT/$APP/VHOST"
 
   rm -f "$APP_VHOST_PATH"