CW-608-Fetch-And-Save-Icons-Of-ERC20-And-SPL-Tokens-When-Adding-Them (#1365)

* feat: Fetch and save icons of SPL tokens when adding them

* feat: Implement fetch and save icons for ERC20 tokens when adding them

* fix: Add moralisApiKey to evm secrets

* Add check to ensure decimals cannot be zero

* - Fallback to adding erc20 token from web3dart
- Wrap fetching spl token icon in a try/catch block

---------

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

lib/polygon/cw_polygon.dart

@@ -129,7 +129,7 @@ class CWPolygon extends Polygon {
   @override
   Future<Erc20Token?> getErc20Token(WalletBase wallet, String contractAddress) async {
     final polygonWallet = wallet as PolygonWallet;
-    return await polygonWallet.getErc20Token(contractAddress);
+    return await polygonWallet.getErc20Token(contractAddress, 'polygon');
   }
 
   @override