cql3/prepare_expr: fix partially preparing function arguments

Before choosing a function, we prepare the arguments that can be
prepared without a receiver. Preparing an argument makes
its type known, which allows to choose the best overload
among many possible functions.

The function that prepared the argument passes the unprepared
argument by mistake. Let's fix it so that it actually uses
the prepared argument.

Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com>

Closes #14786

cql3/expr/prepare_expr.cc

@@ -928,7 +928,7 @@ prepare_function_args_for_type_inference(std::span<const expression> args, data_
         std::optional<expression> prepared_arg_opt = try_prepare_expression(argument, db, keyspace, schema_opt, nullptr);
         auto type = prepared_arg_opt ? std::optional(type_of(*prepared_arg_opt)) : std::nullopt;
         auto expr = prepared_arg_opt ? std::move(*prepared_arg_opt) : argument;
-        partially_prepared_args.emplace_back(as_assignment_testable(std::move(argument), std::move(type)));
+        partially_prepared_args.emplace_back(as_assignment_testable(std::move(expr), std::move(type)));
     }
     return partially_prepared_args;
 }