mGUI: Fix some small memory leaks

src/feature/gui/gui-config.c

@@ -380,4 +380,5 @@ void mGUIShowConfig(struct mGUIRunner* runner, struct GUIMenuItem* extra, size_t
 			}
 		}
 	}
+	GUIMenuItemListDeinit(&menu.items);
 }

src/feature/gui/remap.c

@@ -84,4 +84,5 @@ void mGUIRemapKeys(struct GUIParams* params, struct mInputMap* map, const struct
 			// TODO: Open remap menu
 		}
 	}
+	GUIMenuItemListDeinit(&menu.items);
 }