status: invalidate when needed

In order for the message to actually show up we need to invalidate after setting
the status stack.

widgets/status.go

@@ -81,6 +81,7 @@ func (status *StatusLine) Push(text string, expiry time.Duration) *StatusMessage
 		}
 		status.Invalidate()
 	})()
+	status.Invalidate()
 	return msg
 }