Create ButtonDockHeight constant

[hcourthias]

https://gitlab.com/getluko/front/luko-app-react-native/-/merge_requests/4288#note_1441743996

/*
ButtonDock: https://www.figma.com/file/tOJLNigXQXJqCSKgJFPZn5/App-Streamline-Lukomponents?type=design&node-id=4175%3A2972&t=EMHajXI5oFp6tPWP-1
height + paddingHorizontal + paddingBottom
*/
const ButtonDockHeight = 48 + 16 + 8;