feat(hubble): testnet feature for lenient rpc handling (#4050)

Author: qlp

hubble/hubble.nix

@@ -101,6 +101,11 @@
                 example = 1;
                 default = 200;
               };
+              options.testnet = mkOption {
+                type = types.nullOr types.bool;
+                default = null;
+                description = "Testnet (default false)";
+              };
               options.tx_search_max_page_size = mkOption {
                 type = types.int;
                 description = "Maximum number of transactions to fetch in one page";