SMT2 back-end: Bitwuzla does not support lambda expressions

Disable lambda expressions when producing formulae for Bitwuzla as it
does not support these.

Fixes: #8384

Author: tautschnig

src/solvers/smt2/smt2_conv.cpp

@@ -90,7 +90,7 @@ smt2_convt::smt2_convt(
     use_array_of_bool = true;
     use_as_const = true;
     use_check_sat_assuming = true;
-    use_lambda_for_array = true;
+    use_lambda_for_array = false;
     emit_set_logic = false;
     break;