Added ports as variables in haystack-agent config

Author: vaibhavsawhney

deployment/terraform/haystack-agent/templates/haystack-agent.conf

@@ -1,7 +1,7 @@
 agents {
   spans {
     enabled = true
-    port = 35000
+    port = "${spans_service_port}"
     dispatchers {
       kafka {
         bootstrap.servers = "${kafka_endpoint}"
@@ -13,7 +13,7 @@ agents {
   }
   ossblobs {
     enabled = true
-    port = 35001
+    port = "${blobs_service_port}"
     max.blob.size.in.kb = 512
     dispatchers {
       s3 {