devel/libunicode-contour: fix build on armv7

Same solution as on some other platforms.
Change file for devel/catch2 build dependency to one that is not also
provided by devel/catch.

Approved by: portmgr (build fix blanket)
MFH: 2025Q3

(cherry picked from commit 4f186b7071db773f9b6b9aa7bc12d85bed7fb78a)