Handle CTRL-C as non-redoable abort signal

This is a bit annoying, if for instance "openssl genrsa -aes128"
tries to read a 4+ character size password, but CTRL-C does no longer
work after a RETURN key, since the flag UI_FLAG_REDOABLE is set by
UI_set_result_ex, together with the error "You must type in 4 to 1023 characters".
Thus remove the REDOABLE flag to allow CTRL-C to work.

[extended tests]

Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9170)

(cherry picked from commit f8922b5107d098c78f846c8c999f96111345de8d)