EditInvoiceScreen is not keeping balance state

[jvsena42]

The input is cleared when the user navigates to other screen

[ovitrif]

A few more points I noticed:

state related:

• note and tags reset if tap "Continue" on the edit screen, come back to QR screen and tap "Edit" again.
  • expected: tags, note, and amount are remembered.
  • expected: if I dismiss receive sheet and come back, then the values for tags, note, and amount should be reset

edit invoice screen related:

• IME action on the note text field should dismiss keyboard, currently user has to dismiss keyboard manually

[jvsena42]

Solved in #127