fix(lb-and-routing-table) : Fix routing table and lbs datasource (#5149)

* fix(routing-table): Fix for datasource routing table, handling invalid name

* lbs datasource nil check for subnet name

ibm/service/vpc/data_source_ibm_is_lbs.go

@@ -399,7 +399,9 @@ func getLbs(d *schema.ResourceData, meta interface{}) error {
 				if subnet.CRN != nil {
 					sub[CRN] = *subnet.CRN
 				}
-				sub[name] = *subnet.Name
+				if subnet.Name != nil && *subnet.Name != "" {
+					sub[name] = *subnet.Name
+				}
 				subnetList = append(subnetList, sub)
 
 			}

ibm/service/vpc/data_source_ibm_is_vpc_routing_table.go

@@ -245,6 +245,9 @@ func dataSourceIBMIBMIsVPCRoutingTableRead(context context.Context, d *schema.Re
 				routingTable = &r
 			}
 		}
+		if routingTable == nil {
+			return diag.FromErr(fmt.Errorf("[ERROR] Provided routing table %s cannot be found in the vpc %s", routingTableName, vpcId))
+		}
 	}
 
 	d.SetId(*routingTable.ID)