Hide keys for BTC & LTC (#392)

* Remove WIF and Keys from BTC and LTC wallets in the Wallet seed/keys screen

* Move Title assigning logic to view model

lib/src/screens/wallet_keys/wallet_keys_page.dart

@@ -1,5 +1,4 @@
 import 'package:cake_wallet/utils/show_bar.dart';
-import 'package:flushbar/flushbar.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/services.dart';
@@ -13,7 +12,7 @@ class WalletKeysPage extends BasePage {
   WalletKeysPage(this.walletKeysViewModel);
 
   @override
-  String get title => S.current.wallet_keys;
+  String get title => walletKeysViewModel.title;
 
   final WalletKeysViewModel walletKeysViewModel;
 
@@ -27,10 +26,7 @@ class WalletKeysPage extends BasePage {
                 separatorBuilder: (context, index) => Container(
                       height: 1,
                       padding: EdgeInsets.only(left: 24),
-                      color: Theme.of(context)
-                          .accentTextTheme
-                          .title
-                          .backgroundColor,
+                      color: Theme.of(context).accentTextTheme.title.backgroundColor,
                       child: Container(
                         height: 1,
                         color: Theme.of(context).dividerColor,
@@ -43,8 +39,7 @@ class WalletKeysPage extends BasePage {
                   return GestureDetector(
                     onTap: () {
                       Clipboard.setData(ClipboardData(text: item.value));
-                      showBar<void>(context,
-                          S.of(context).copied_key_to_clipboard(item.title));
+                      showBar<void>(context, S.of(context).copied_key_to_clipboard(item.title));
                     },
                     child: StandartListRow(
                       title: item.title + ':',