fix unloading containers which also have other types of pockets

[maspri]

Summary

Bugfixes "fix unloading containers which also have other types of pockets"

Purpose of change

fix #55481, fix #54330

Describe the solution

If an item has a CONTAINER pocket it is treated as container by character::unload and nothing else.

Before, containers with additional multiple pocket types, for example rc_car or multi_cooker, still had all their standard pockets unloaded as a side-effect. This included unloading batteries.

Then pr #53250 changed this to only unloading CONTAINER pockets (which makes sense):

@@ -9897,7 +9897,7 @@ bool Character::unload( item_location &loc, bool bypass_activity )
         }

         int moves = 0;
-        for( item *contained : it.all_items_top() ) {
+        for( item *contained : it.all_items_top( item_pocket::pocket_type::CONTAINER, true ) ) {
             moves += this->item_handling_cost( *contained );
         }
         assign_activity( player_activity( unload_activity_actor( moves, loc ) ) );

However, batteries are now no longer unloaded, causing #55481 and #54330.

The fix in this pr restores the old behaviour by explicitly unloading all standard pocket types of a container using the function introduced in pr #53250, maintaining the functionality of the pr.

Describe alternatives you've considered

There could probably be some better refactoring of character::unload, but I feel this changes the code as little as possible avoiding regressions.
There could be unintended side-effects with the originial behaviour, for example if a new gun is added which has a snack compartment. This gun would be treated as container and mods with magazines could no longer be unloaded. But until then this should be fine 😃

Testing