Review bool comparisons (variables in Signals, empty lists etc)

[miskatonicstudio]

Godot v4 seems to no longer allow for using empty lists or empty variables (e.g. empty strings) as boolean (e.g. with the != operator). As a result, some changes has been made, mostly by adding is_empty to different checks in the framework:

addons/goat/settings/SettingsSlider.gd:	if not settings_section.is_empty() and not settings_key.is_empty():
addons/goat/settings/SettingsSlider.gd:	if not settings_section.is_empty() and not settings_key.is_empty():
addons/goat/settings/SettingsCheckButton.gd:	if not settings_section.is_empty() and not settings_key.is_empty():
addons/goat/settings/SettingsCheckButton.gd:	if not settings_section.is_empty() and not settings_key.is_empty():
addons/goat/globals/goat_inventory.gd:		if not _items.is_empty():
addons/goat/globals/goat_settings.gd:	if loaded_locales.is_empty():
addons/goat/main_scenes/Player.gd:			if overlapping_bodies.is_empty():
addons/goat/main_scenes/DetailedInteraction.gd:	if interactive_item.unique_name.is_empty():
addons/goat/helper_scenes/InventoryItems.gd:		not goat_inventory.get_items().is_empty()
addons/goat/helper_scenes/InventoryItems.gd:	var inventory_empty = new_items.is_empty()

All similar checks should be reviewed and corrected as well, unless future versions of Godot v4 bring back the "cast to boolean" feature. In that case, the check can be changed to != again (which is more concise).

[miskatonicstudio]

It turned out this was a bug in Godot 4.0.3. GOAT now uses Godot 4.1.1, and therefore this is fixed. All the changes can now be reverted ;)