gui: Ensure tx send error highlight is visible
gui: Ensure tx send error highlight is visible

If sending to multiple recipients and one of the recipient fields is malformed,
the highlighted field may not be visible due to being scrolled out of view,
leading to a confusing lack of error feedback when clicking Send. To avoid this
problem ensure the first field containing an error is scrolled into view
when Send is clicked.


Former-commit-id: fd4caf4e8a997ef3e732109b6983d0b7fab176b7
syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin