fix: correct category for 0x protocol

Changed category to match valid categories in categories.json

Author: Antic-swap

testnet/0x.json

@@ -3,7 +3,7 @@
     "description": "Swap API v2, embedded swaps in any app",
     "live": true,
     "categories": [
-        "DeFi::DEX Aggregator"
+        "DeFi::DEX"
     ],
     "addresses": {
         "unknown0": "0x07F37e56bc55B7F927807171647c2EEE95C78f31",