[test] Fix xpack test to check for http_address stats only if the web…

…server is enabled (#16525)

Set the 'api.enabled' setting to reflect the flag webserver_enabled and consequently test for http_address presence in settings iff the web server is enabled.

x-pack/spec/monitoring/inputs/metrics/stats_event_factory_spec.rb

@@ -50,6 +50,7 @@
   let(:pipeline_settings) { LogStash::Runner::SYSTEM_SETTINGS.clone.merge({
     "pipeline.id" => "main",
     "config.string" => config,
+    "api.enabled" => webserver_enabled,
   }) }
 
   let(:agent) { LogStash::Agent.new(pipeline_settings) }
@@ -70,14 +71,16 @@
     # easily observable, feel free to refactor with a better "timing" test here.
     wait(60).for { collector.snapshot_metric.metric_store.size }.to be >= 72
 
-    # Wait http server is up
-    wait(120).for {
-      begin
-        collector.snapshot_metric.metric_store.get_shallow(:http_address)
-      rescue LogStash::Instrument::MetricStore::MetricNotFound => e
-        nil
-      end
-    }.not_to be_nil
+    if webserver_enabled
+      # Wait http server is up
+      wait(120).for {
+        begin
+          collector.snapshot_metric.metric_store.get_shallow(:http_address)
+        rescue LogStash::Instrument::MetricStore::MetricNotFound => e
+          nil
+        end
+      }.not_to be_nil
+    end
   end
 
   after :each do
@@ -86,14 +89,19 @@
     LogStash::SETTINGS.set_value("monitoring.enabled", false)
   end
 
- context "new model" do
-   it_behaves_like("new model monitoring event with webserver setting") do
-     let(:webserver_enabled) {false}
-   end
-   it_behaves_like("new model monitoring event with webserver setting") do
-     let(:webserver_enabled) {true}
-   end
- end
+  context "new model" do
+    context "with webserver disabled" do
+      it_behaves_like("new model monitoring event with webserver setting") do
+        let(:webserver_enabled) {false}
+      end
+    end
+
+    context "with webserver enabled" do
+      it_behaves_like("new model monitoring event with webserver setting") do
+        let(:webserver_enabled) {true}
+      end
+    end
+  end
 
  # TODO: fix issue https://github.com/elastic/logstash/issues/12711
  xcontext "old model" do