fix otherwise unitialized variables, found in #31694

(cherry picked from commit 4817595c0e)

scene/3d/physics_body.h

@@ -162,6 +162,7 @@ protected:
 		ShapePair(int p_bs, int p_ls) {
 			body_shape = p_bs;
 			local_shape = p_ls;
+			tagged = false;
 		}
 	};
 	struct RigidBody_RemoveAction {

scene/animation/animation_tree.cpp

@@ -1412,6 +1412,7 @@ void AnimationTree::_update_properties_for_node(const String &p_base_path, Ref<A
 		Vector<Activity> activity;
 		for (int i = 0; i < node->get_input_count(); i++) {
 			Activity a;
+			a.activity = 0;
 			a.last_pass = 0;
 			activity.push_back(a);
 		}