fix(chains): drop node URLs that embed Nova's Infura keys

Nova's configs carry Nova's own Infura project keys inside node URLs, and
every sync copied them into ours: Ethereum had four keyed Infura nodes and
Base one, across 43 published files. Our Android build already fills
`{INFURA_API_KEY}` from our own secret; the keyed URLs used another
organisation's quota and would break for every user when Nova rotates them.

- sync_from_nova.py strips nodes whose URL embeds an Infura key, and drops a
  chain left with no node (only Ethereum - Goerli, a retired testnet, in the
  dev files); merge-chains.py applies the same filter
- the published chain files are rewritten with that filter; nothing else in
  them changes (each file round-trips byte for byte through json.dump)
- check_pezkuwi_integrity.py refuses a keyed Infura URL under chains/

chains/v21/chains_dev.json

@@ -3751,14 +3751,6 @@
         "url": "https://1rpc.io/eth",
         "name": "One rpc node"
       },
-      {
-        "url": "wss://mainnet.infura.io/ws/v3/25bd0a6e359240529b237e5dd8b19e1f",
-        "name": "Infura node 3"
-      },
-      {
-        "url": "wss://mainnet.infura.io/ws/v3/1e69544301064ef19edb194a14fb75f3",
-        "name": "Infura node 2"
-      },
       {
         "url": "wss://mainnet.infura.io/ws/v3/{INFURA_API_KEY}",
         "name": "Infura test node"
@@ -3834,51 +3826,6 @@
       "noSubstrateRuntime"
     ]
   },
-  {
-    "chainId": "eip155:5",
-    "name": "Ethereum - Goerli",
-    "assets": [
-      {
-        "assetId": 0,
-        "symbol": "ETH",
-        "priceId": "ethereum",
-        "type": "evmNative",
-        "icon": "ETH.svg",
-        "precision": 18
-      }
-    ],
-    "nodes": [
-      {
-        "url": "wss://goerli.infura.io/ws/v3/25bd0a6e359240529b237e5dd8b19e1f",
-        "name": "Infura test node"
-      }
-    ],
-    "explorers": [
-      {
-        "name": "Etherscan",
-        "extrinsic": "https://goerli.etherscan.io/tx/{hash}",
-        "account": "https://goerli.etherscan.io/address/{address}"
-      }
-    ],
-    "externalApi": {
-      "history": [
-        {
-          "type": "etherscan",
-          "url": "https://api-goerli.etherscan.io/api",
-          "parameters": {
-            "assetType": "evm"
-          }
-        }
-      ]
-    },
-    "icon": "https://raw.githubusercontent.com/novasamatech/nova-utils/master/icons/chains/gradient/Ethereum_Goerli.svg",
-    "addressPrefix": 5,
-    "options": [
-      "testnet",
-      "ethereumBased",
-      "noSubstrateRuntime"
-    ]
-  },
   {
     "chainId": "9eb76c5184c4ab8679d2d5d819fdf90b9c001403e9e17da2e14b6d8aec4029c6",
     "parentId": "91b171bb158e2d3848fa23a9f1c25182fb8e20313b2c1eb49219da7a70ce90c3",