UI2: Unify show_info variants on T2T1

[matejcik]

There are currently four functions: show_info, show_success, show_error, show_warning, that are on the Rust side only differentiated by icon & button style.

For API unification with T2B1 (which does not use icons and colors), it would be great if there was one function show_popup? show modal? that accepts a string or an enum specifying the overall "style". That way T2B1 code can accept them as dummy arguments, while T2T1 code can make use of the value.

[obrusvit]

Referring #4322