Trac sagemath#34769: use libgap in simplicial_complex

this is just a 1-line change.

A part of sagemath#26902

URL: https://trac.sagemath.org/34769
Reported by: dimpase
Ticket author(s): Dima Pasechnik
Reviewer(s): John Palmieri

src/sage/topology/simplicial_complex.py

@@ -4128,7 +4128,7 @@ def fundamental_group(self, base_point=None, simplify=True):
             return self.connected_component(Simplex([base_point])).fundamental_group(simplify=simplify)
 
         from sage.groups.free_group import FreeGroup
-        from sage.interfaces.gap import gap
+        from sage.libs.gap.libgap import libgap as gap
         G = self.graph()
         # If the vertices and edges of G are not sortable, e.g., a mix
         # of str and int, Sage+Python 3 may raise a TypeError when