refactor: drop unused value_exists from report functions

The `value_exists` variable in the report info-flag loop is no longer read after the `not deployed` failure was removed, and was already unused in domains, haproxy-vhosts, traefik-vhosts, caddy-vhosts, and openresty-vhosts. Drop the declaration and the trailing assignment so the loop reads cleanly across all plugins.

plugins/scheduler-docker-local/internal-functions

@@ -69,14 +69,13 @@ cmd-scheduler-docker-local-report-single() {
     done
   else
     local match=false
-    local value_exists=false
     for flag in "${flag_map[@]}"; do
       valid_flags="${valid_flags} $(echo "$flag" | cut -d':' -f1)"
       if [[ "$flag" == "${INFO_FLAG}:"* ]]; then
         value=${flag#*: }
         size="${#value}"
         if [[ "$size" -ne 0 ]]; then
-          echo "$value" && match=true && value_exists=true
+          echo "$value" && match=true
         else
           match=true
         fi