devel/libunicode-contour: Fix build when samurai is used instead of ninja

When samurai is used instead of ninja, python is not pulled in as its
dependency. The build process requires python's existence so the port
must explictly depend on python in build time.

PR: 292683
Reported by: Eric Camachat <eric@camachat.org>
MFH: 2026Q1

(cherry picked from commit 460e62cc3548b28a331954257679793713631951)