remove unused function argument

Author: Bruno-TT

src/sage/groups/matrix_gps/finitely_generated_gap.py

@@ -905,7 +905,7 @@ def invariants_of_degree(self, deg, chi=None, R=None):
                     break
         return list(inv)
 
-def _new_invariant_is_linearly_independent(F, invariants, R):
+def _new_invariant_is_linearly_independent(F, invariants):
     """
     EXAMPLES ::
         sage: gens = [matrix(QQ, [[-1,1],[-1,0]]), matrix(QQ, [[0,1],[1,0]])]