Configure MQTT broker hostname based on execution context (#993)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: thomasnordquist <7721625+thomasnordquist@users.noreply.github.com>

.github/workflows/copilot-setup-steps.yml

@@ -14,6 +14,9 @@ on:
 jobs:
   copilot-setup-steps:
     runs-on: ubuntu-latest
+    env:
+      TESTS_MQTT_BROKER_HOST: localhost
+      TESTS_MQTT_BROKER_PORT: 1883
 
     steps:
       - name: Checkout code