[TF] Add evpn_network_id output for vmx resource

- added evpn_network_id to vmx output
- enable dhcp for evpn subnet

Related-PROD: PRODX-22375
Change-Id: I8d32939dbdaebc7cb1d3e348e8602bc5a431b0f6
diff --git a/de/heat-templates/fragments/vMX.yaml b/de/heat-templates/fragments/vMX.yaml
index f0dd60c..67fb1ad 100644
--- a/de/heat-templates/fragments/vMX.yaml
+++ b/de/heat-templates/fragments/vMX.yaml
@@ -145,3 +145,6 @@
   re_floating_ip:
     description: Floating IP address of server in public network
     value: { get_attr: [ server_floating_ip, floating_ip_address ] }
+  evpn_network_id:
+    description: Id of network for evpn tests
+    value: { get_attr: [ evpn_network, evpn_network_id ] }
diff --git a/de/heat-templates/fragments/vmx-components/network/evpn_network.yaml b/de/heat-templates/fragments/vmx-components/network/evpn_network.yaml
index 384f3c0..772d3fd 100644
--- a/de/heat-templates/fragments/vmx-components/network/evpn_network.yaml
+++ b/de/heat-templates/fragments/vmx-components/network/evpn_network.yaml
@@ -16,7 +16,7 @@
     type: OS::Neutron::Subnet
     properties:
       network: { get_resource: network }
-      enable_dhcp: false
+      enable_dhcp: true
       cidr: { get_param: evpn_network_cidr }
       gateway_ip: ~
       allocation_pools: