fix: remove unnecessary test

ensuring `nothing` is not stored as indepsym is covered in SII tests

Author: AayushSabharwal

test/symbolic_indexing_interface_test.jl

@@ -70,13 +70,9 @@ dx = DiffEqArray([[f(x), f2(x)] for x in t],
 @test constant_structure(dx)
 @info "TEST 29"
 
-dx = DiffEqArray([[f(x), f2(x)] for x in t], t; variables = [:a, :b])
-@test_throws Exception dx[nothing] # make sure it isn't storing [nothing] as indepsym
-@info "TEST 30"
-
 ABC = @SLVector (:a, :b, :c);
 A = ABC(1, 2, 3);
 B = RecursiveArrayTools.DiffEqArray([A, A], [0.0, 2.0]);
 @test getindex(B, :a) == [1, 1]
-@info "TEST 31"
+@info "TEST 30"