fix: validate mnemonic format when importing a existing key

src/app/onboarding/view.nim

@@ -86,14 +86,14 @@ QtObject:
 
   proc importMnemonic(self: OnboardingView, mnemonic: string): string {.slot.} =
     try:
-      let importResult = self.status.accounts.importMnemonic(mnemonic)
+      let importResult = self.status.accounts.importMnemonic(mnemonic.strip())
       result = importResult.toJson
       self.currentAccount.setAccount(importResult)
     except StatusGoException as e:
       result = StatusGoError(error: e.msg).toJson
 
   proc validateMnemonic*(self: OnboardingView, mnemonic: string): string {.slot.} =
-     result = self.status.wallet.validateMnemonic(mnemonic)
+    result = self.status.wallet.validateMnemonic(mnemonic.strip())
 
   proc storeDerivedAndLogin(self: OnboardingView, password: string): string {.slot.} =
     try:

src/app/wallet/view.nim

@@ -140,7 +140,7 @@ QtObject:
     result = self.status.wallet.generateNewAccount(password, accountName, color)
 
   proc addAccountsFromSeed*(self: WalletView, seed: string, password: string, accountName: string, color: string): string {.slot.} =
-    result = self.status.wallet.addAccountsFromSeed(seed, password, accountName, color)
+    result = self.status.wallet.addAccountsFromSeed(seed.strip(), password, accountName, color)
 
   proc addAccountsFromPrivateKey*(self: WalletView, privateKey: string, password: string, accountName: string, color: string): string {.slot.} =
     result = self.status.wallet.addAccountsFromPrivateKey(privateKey, password, accountName, color)

ui/imports/Utils.qml

@@ -30,8 +30,11 @@ QtObject {
     }
 
     function isMnemonic(value) {
-        // Do we support other length than 12?
-        return value.split(/\s|,/).length === 12
+        if(!value.match(/^([a-z\s]+)$/)){
+            return false;
+        }
+        var len = value.split(/\s|,/).length;
+        return  len >= 12 && len <= 24 && len % 3 == 0;
     }
 
     function compactAddress(addr, numberOfChars) {

ui/onboarding/ExistingKey.qml

@@ -1,5 +1,6 @@
 import QtQuick 2.13
 import QtQuick.Controls 2.13
+import "../imports"
 
 Item {
     property var onClosed: function () {}
@@ -14,7 +15,14 @@ Item {
         property bool wentNext: false
         id: enterSeedPhraseModal
         onConfirmSeedClick: function (mnemonic) {
-            let error = onboardingModel.validateMnemonic(mnemonic)
+            let error = "";
+            
+            if(!Utils.isMnemonic(mnemonic)){
+                error = qsTr("Invalid mnemonic")
+            } else {
+                error = onboardingModel.validateMnemonic(mnemonic)
+            }
+
             if (error != "") {
               errorSound.play()
               invalidSeedPhraseModal.error = error