CW-1103:Token Validation Issues (#2327)

* feat(token_validation): Improve flow for adding new tokens across wallets

This change:
- Implements check to see if a token is already added, preventing duplicates
- Triggers dialog warning if its a duplicate token
- Takes EVM Chains contract adddress case-insensitivity when making checks for potential scams.

* refactor(token_validation): Modify token management flow

This change:
- Removes duplicate token check during token addition in EVMChainWalletBase.
- Introduces a flag to indicate if a token is being edited
- Adjusts token addition validation to bypass checks when editing an existing token.

* Update lib/src/screens/dashboard/edit_token_page.dart

---------

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

tool/configure.dart

@@ -760,6 +760,7 @@ abstract class Ethereum {
   void setLedgerConnection(WalletBase wallet, ledger.LedgerConnection connection);
   Future<List<HardwareAccountData>> getHardwareWalletAccounts(LedgerViewModel ledgerVM, {int index = 0, int limit = 5});
   List<String> getDefaultTokenContractAddresses();
+  bool isTokenAlreadyAdded(WalletBase wallet, String contractAddress);
 }
   """;
 
@@ -870,6 +871,7 @@ abstract class Polygon {
   void setLedgerConnection(WalletBase wallet, ledger.LedgerConnection connection);
   Future<List<HardwareAccountData>> getHardwareWalletAccounts(LedgerViewModel ledgerVM, {int index = 0, int limit = 5});
   List<String> getDefaultTokenContractAddresses();
+  bool isTokenAlreadyAdded(WalletBase wallet, String contractAddress);
 }
   """;
 
@@ -1156,6 +1158,7 @@ abstract class Solana {
   List<int>? getValidationLength(CryptoCurrency type);
   double? getEstimateFees(WalletBase wallet);
   List<String> getDefaultTokenContractAddresses();
+  bool isTokenAlreadyAdded(WalletBase wallet, String contractAddress);
 }
 
   """;
@@ -1234,6 +1237,7 @@ abstract class Tron {
   
   void updateTronGridUsageState(WalletBase wallet, bool isEnabled);
   List<String> getDefaultTokenContractAddresses();
+  bool isTokenAlreadyAdded(WalletBase wallet, String contractAddress);
 }
   """;
 
@@ -1308,6 +1312,7 @@ abstract class Zano {
   String getAddress(WalletBase wallet);
   bool validateAddress(String address);
   Map<String, List<int>> debugCallLength();
+  bool isTokenAlreadyAdded(WalletBase wallet, String contractAddress);
 }
 """;
   const zanoEmptyDefinition = 'Zano? zano;\n';