[apps/calculations] Add 'ans' when the text field starts with '^2'

Change-Id: I8cc8a5455f934e875ef4ba1e8388d16210630107

apps/calculation/text_field.cpp

@@ -22,6 +22,7 @@ bool TextField::handleEvent(Ion::Events::Event event) {
        event == Ion::Events::Plus ||
        event == Ion::Events::Minus ||
        event == Ion::Events::Power ||
+       event == Ion::Events::Square ||
        event == Ion::Events::Division)) {
     if (!isEditing()) {
       setEditing(true);