[libc++] Remove the type_traits includes from limits and new

type_traits is currently unable to include __type_traits/noexcept_move_assign_container.h, because it would cause several include cycles.

type_traits -> __type_traits/noexcept_move_assign_container.h -> __memory/allocator_traits.h -> __memory/construct_at.h -> new -> exception -> type_traits

type_traits -> __type_traits/noexcept_move_assign_container.h -> __memory/allocator_traits.h -> __memory/construct_at.h -> new -> type_traits

type_traits -> __type_traits/noexcept_move_assign_container.h -> __memory/allocator_traits.h -> limits -> type_traits

This is a problem for clang modules after the std mega module is broken up (D144322), because it becomes a module cycle which is a hard error.

Unconditionally remove the type_traits includes from limits and new in all versions, and also remove the exception include from new. (These are already removed in C++23.)

Reviewed By: ldionne, Mordante, #libc

Differential Revision: https://reviews.llvm.org/D153214