Fix setting of token balance on account switch in send screen from field.

ui/app/components/send_/send-content/send-from-row/send-from-row.container.js

@@ -39,7 +39,7 @@ function mapDispatchToProps (dispatch) {
     setSendTokenBalance: (usersToken, selectedToken) => {
         if (!usersToken) return
 
-        const tokenBalance = calcTokenBalance(usersToken, selectedToken)
+        const tokenBalance = calcTokenBalance({ usersToken, selectedToken })
         dispatch(setSendTokenBalance(tokenBalance))
     },
   }

ui/app/components/send_/send-content/send-from-row/tests/send-from-row-container.test.js

@@ -29,7 +29,7 @@ proxyquire('../send-from-row.container.js', {
     getSendFromObject: (s) => `mockFrom:${s}`,
   },
   './send-from-row.selectors.js': { getFromDropdownOpen: (s) => `mockFromDropdownOpen:${s}` },
-  '../../send.utils.js': { calcTokenBalance: (a, b) => a + b },
+  '../../send.utils.js': { calcTokenBalance: ({ usersToken, selectedToken }) => usersToken + selectedToken },
   '../../../../actions': actionSpies,
   '../../../../ducks/send.duck': duckActionSpies,
 })

ui/app/components/send_/send.utils.js

@@ -158,7 +158,7 @@ function getParamsForGasEstimate (selectedAddress, symbol, data) {
 
 function calcTokenBalance ({ selectedToken, usersToken }) {
   const { decimals } = selectedToken || {}
-  return calcTokenAmount(usersToken.balance.toString(), decimals)
+  return calcTokenAmount(usersToken.balance.toString(), decimals) + ''
 }
 
 function doesAmountErrorRequireUpdate ({