refactor: lndrest get_payment_status and pay_invoice use api v2 (#3470)

Co-authored-by: Vlad Stan <stan.v.vlad@gmail.com>

tests/wallets/fixtures/json/fixtures_rest.json

@@ -1092,7 +1092,7 @@
         },
         "lndrest": {
           "pay_invoice_endpoint": {
-            "uri": "/v1/channels/transactions",
+            "uri": "/v2/router/send",
             "headers": {
               "Grpc-Metadata-macaroon": "eNcRyPtEdMaCaRoOn",
               "User-Agent": "LNbits/Tests"
@@ -1204,11 +1204,12 @@
                   },
                   "response_type": "json",
                   "response": {
-                    "payment_hash": "41UmpD0E6YVZTA36uEiBT1JLHHhlmOyaY77dstcmrJY=",
-                    "payment_route": {
-                      "total_fees_msat": 30000
-                    },
-                    "payment_preimage": "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA="
+                    "result": {
+                      "status": "SUCCEEDED",
+                      "payment_hash": "e35526a43d04e985594c0dfab848814f524b1c786598ec9a63beddb2d726ac96",
+                      "fee_msat": 30000,
+                      "payment_preimage": "0000000000000000000000000000000000000000000000000000000000000000"
+                    }
                   }
                 }
               ]
@@ -2625,16 +2626,6 @@
                       "status": "FAILED"
                     }
                   }
-                },
-                {
-                  "description": "error code 5",
-                  "response_type": "stream",
-                  "response": {
-                    "error": {
-                      "code": 5,
-                      "message": "payment isn't initiated"
-                    }
-                  }
                 }
               ]
             },