Unify "not enough funds" errors

[slaweet]

Expected behaviour

All transaction types should check balance at the beginning and display a unified error message.

Actual behaviour

• Send: "Insufficient funds" error message under the "amount" input
• Vote: red error toast saying " Account does not have enough LSK: 9192292151089507854L balance: 0" after clicking "Confirm" button
• Register as delegate: "Account does not have enough LSK: 9192292151089507854L balance: 0" message after clicking "Register" button
• Register second passphrase: "You have insufficient funds to register a second passphrase." Error alert dialog after clicking "Register" button