Fix double call of restore_input

restore_input is called in State::rcv_event on arrival of a fork
finished event:

```
            UIEvent::Fork(ForkType::Finished) => {
                self.switch_to_main_screen();
                self.switch_to_alternate_screen();
                self.context.restore_input();
                return;
            }
```

So there shouldn't be an extra call here.

src/components/mail/compose.rs

@@ -934,7 +934,6 @@ impl Component for Composer {
                     }
                 }
                 self.initialized = false;
-                context.restore_input();
                 self.dirty = true;
                 return true;
             }