Don't fail if one request fails in getTokensBalances

If one request failed, the whole batch would fail.
This caused issue as one of the contract is constantly returning an
error now, and essentially there was not way to fetch balance.
Also extend the timeout to 20s as we throw 165 request to Infura in one
go and it takes its time to reply to those, although it seems like we
should batch them on our side instead of sending them all cuncurrently.

VERSION

@@ -1 +1 @@
-0.62.7
+0.62.8

services/wallet/balance.go

@@ -10,10 +10,13 @@ import (
 	"github.com/ethereum/go-ethereum/accounts/abi/bind"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/ethclient"
+	"github.com/ethereum/go-ethereum/log"
 
 	"github.com/status-im/status-go/services/wallet/ierc20"
 )
 
+var requestTimeout = 20 * time.Second
+
 // GetTokensBalances takes list of accounts and tokens and returns mapping of token balances for each account.
 func GetTokensBalances(parent context.Context, client *ethclient.Client, accounts, tokens []common.Address) (map[common.Address]map[common.Address]*hexutil.Big, error) {
 	var (
@@ -22,7 +25,7 @@ func GetTokensBalances(parent context.Context, client *ethclient.Client, account
 		response = map[common.Address]map[common.Address]*hexutil.Big{}
 	)
 	// requested current head to request balance on the same block number
-	ctx, cancel := context.WithTimeout(parent, 3*time.Second)
+	ctx, cancel := context.WithTimeout(parent, requestTimeout)
 	header, err := client.HeaderByNumber(ctx, nil)
 	cancel()
 	if err != nil {
@@ -35,16 +38,21 @@ func GetTokensBalances(parent context.Context, client *ethclient.Client, account
 			return nil, err
 		}
 		for _, account := range accounts {
+			// Why we are doing this?
 			account := account
 			group.Add(func(parent context.Context) error {
-				ctx, cancel := context.WithTimeout(parent, 3*time.Second)
+				ctx, cancel := context.WithTimeout(parent, requestTimeout)
 				balance, err := caller.BalanceOf(&bind.CallOpts{
 					BlockNumber: header.Number,
 					Context:     ctx,
 				}, account)
 				cancel()
+				// We don't want to return an error here and prevent
+				// the rest from completing
 				if err != nil {
-					return err
+					log.Error("can't fetch erc20 token balance", "account", account, "token", token, "error", err)
+
+					return nil
 				}
 				mu.Lock()
 				_, exist := response[account]

services/wallet/balance_test.go

@@ -131,7 +131,7 @@ func (s *BalancesSuite) TestNoAccounts() {
 
 func (s *BalancesSuite) TestTokenNotDeployed() {
 	_, err := GetTokensBalances(context.Background(), s.client, s.accounts, []common.Address{{0x01}})
-	s.Require().EqualError(err, "no contract code at given address")
+	s.Require().NoError(err)
 }
 
 func (s *BalancesSuite) TestInterrupted() {