Eliminate legacy checks in `curses.__init__`

[picnixz]

Feature or enhancement

Proposal:

Some checks in curses.__init__ are now obsolete, essentially because of how the C functions are now implemented. For instance, start_color() checks for whether _curses.COLORS exists, but it will always exist if the call to _curses.start_color() succeeds.

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs

• gh-133575: eliminate legacy checks in curses.__init__ #133576