fix: handle AD materialization

Author: avik-pal

src/core/generalized_first_order.jl

@@ -202,6 +202,8 @@ function SciMLBase.__init(
             linesearch_ad = alg.forward_ad === nothing ?
                             (alg.reverse_ad === nothing ? alg.jacobian_ad :
                              alg.reverse_ad) : alg.forward_ad
+            linesearch_ad = get_concrete_forward_ad(
+                linesearch_ad, prob, False; check_forward_mode = false)
             linesearch_cache = init(
                 prob, alg.linesearch, fu, u; stats, autodiff = linesearch_ad, kwargs...)
             GB = :LineSearch