DatePickerButton does not scale well when text sizes are changed

**Describe the bug**
It is not possible to use the DatePickerButton object with larger text font sizes, as the buttons and text become crushed. It is also not possible to override the spacing options since these are overridde within the draw function of the DatePickerPopup.

This is an issue from an accessibility perspective, as users who require a larger font cannot currently use the DatePicker effectively.

**To Reproduce**
Set Button and Text objects using `style.text_styles` and set the `button` and `body` fonts to be size 20.
create a DatePickerButton and view the result:


I believe the issue comes from https://github.com/emilk/egui/blob/527f4bfdf69f1ae2eb204258f872cfc2da20433f/crates/egui_extras/src/datepicker/popup.rs#L58

Tested on both web and native windows, issue is shared across all.