CW-1175-Implement-swaps.xyz-swap-provider (#2526)

* Integrate SwapsXYZ

* Remove print

* enhance SwapsXyz EVM token swap handling

* Disable fixed rate support in SwapsXyz provider

* enable fixed rate swap

* fix timestamp parsing

* remove sender and recipient address from fetchRate

* Improve SwapsXYZ trade approval logic

* fix trade ID overflow

* add Base chain support for  swaps xyz

* Update lib/view_model/exchange/exchange_trade_view_model.dart

Co-authored-by: Omar Hatem <omarh.ismail1@gmail.com>

* add missing support for Base

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Co-authored-by: Omar Hatem <omarh.ismail1@gmail.com>

tool/utils/secret_key.dart

@@ -82,6 +82,7 @@ class SecretKey {
     SecretKey('chainflipAffiliateFee', () => ''),
     SecretKey('kryptonimApiKey', () => ''),
     SecretKey('walletGroupSalt', () => hex.encode(encrypt.Key.fromSecureRandom(16).bytes)),
+    SecretKey('swapsXyzApiKey', () => ''),
   ];
 
   static final evmChainsSecrets = [