Fix Pezkuwi staking configuration to match Polkadot pattern

Source changes (pezkuwi-overlay/chains/pezkuwi-chains.json):
- Pezkuwi Relay Chain: Add stakingMaxElectingVoters: 22500
- Pezkuwi Asset Hub HEZ: Change staking from ["nomination-pools"] to ["relaychain"]
- Pezkuwi Asset Hub: Add stakingMaxElectingVoters: 22500

This fixes the "Loading staking info" issue where findStakingTypeBackingNominationPools()
was failing because nomination-pools had no backing staking type.

Regenerated all chain versions via sync_from_nova.py

chains/v2/chains_dev.json

@@ -56,7 +56,8 @@
       "themeColor": "#009639",
       "defaultBlockTimeMillis": 6000,
       "feeViaRuntimeCall": true,
-      "disabledCheckMetadataHash": true
+      "disabledCheckMetadataHash": true,
+      "stakingMaxElectingVoters": 22500
     }
   },
   {
@@ -130,7 +131,7 @@
         "name": "Hezkurd",
         "priceId": "hezkurd",
         "staking": [
-          "nomination-pools"
+          "relaychain"
         ],
         "type": "native",
         "icon": "https://raw.githubusercontent.com/pezkuwichain/pezkuwi-wallet-utils/main/icons/tokens/HEZ.png",
@@ -220,6 +221,7 @@
       "feeViaRuntimeCall": true,
       "disabledCheckMetadataHash": true,
       "relaychainAsNative": true,
+      "stakingMaxElectingVoters": 22500,
       "timelineChain": "bb4a61ab0c4b8c12f5eab71d0c86c482e03a275ecdafee678dea712474d33d75"
     }
   },