Refactor customer_service_client.ps1 to use parameterized StartUrl for flexibility

Author: AnatoliB

samples-v2/openai_agents/customer_service/customer_service_client.ps1

@@ -1,6 +1,10 @@
+param(
+    [string]$StartUrl = 'http://localhost:7071/api/orchestrators/customer_service'
+)
+
 $ErrorActionPreference = 'Stop'
 
-$orchestration = Invoke-RestMethod 'http://localhost:7071/api/orchestrators/customer_service'
+$orchestration = Invoke-RestMethod $StartUrl
 
 
 while ($true) {