Pin FactoMineR via cran-mirror remote, not version constraint

pak refuses to backtrack to FactoMineR 2.14 from CRAN's latest index
(sessioninfo dep conflict). Point it at the cran/FactoMineR GitHub
mirror's 2.14 tag instead.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: MaxHalford

tests/DESCRIPTION

@@ -2,4 +2,6 @@ Package: prince-test
 Version: 0.0.0.1
 Title: Test dependencies
 Imports:
-    FactoMineR (== 2.14)
+    FactoMineR
+Remotes:
+    cran/FactoMineR@2.14