removes location property from load balancer backend address pool properties (#18862)

Co-authored-by: Gema Beltran <[email protected]>

Author: gramila

specification/network/resource-manager/Microsoft.Network/stable/2020-11-01/loadBalancer.json

@@ -1548,10 +1548,6 @@
     },
     "BackendAddressPoolPropertiesFormat": {
       "properties": {
-        "location": {
-          "type": "string",
-          "description": "The location of the backend address pool."
-        },
         "loadBalancerBackendAddresses": {
           "type": "array",
           "items": {