Revert "fix np nan convention."

This reverts commit c68df59.

Author: B1ueber2y

limap/pointsfm/database.py

@@ -197,8 +197,8 @@ def add_image(
         self,
         name,
         camera_id,
-        prior_q=np.full(4, np.nan),
-        prior_t=np.full(3, np.nan),
+        prior_q=np.full(4, np.NaN),
+        prior_t=np.full(3, np.NaN),
         image_id=None,
     ):
         cursor = self.execute(