Particles: Properly initialize angular velocity parameter

Right now it would take garbage values when loading scenes,
which could end up written to the scene file.

scene/2d/cpu_particles_2d.cpp

@@ -1392,9 +1392,9 @@ CPUParticles2D::CPUParticles2D() {
 	set_spread(45);
 	set_flatness(0);
 	set_param(PARAM_INITIAL_LINEAR_VELOCITY, 1);
+	set_param(PARAM_ANGULAR_VELOCITY, 0);
 	set_param(PARAM_ORBIT_VELOCITY, 0);
 	set_param(PARAM_LINEAR_ACCEL, 0);
-	set_param(PARAM_ANGULAR_VELOCITY, 0);
 	set_param(PARAM_RADIAL_ACCEL, 0);
 	set_param(PARAM_TANGENTIAL_ACCEL, 0);
 	set_param(PARAM_DAMPING, 0);

scene/3d/cpu_particles.cpp

@@ -1460,6 +1460,7 @@ CPUParticles::CPUParticles() {
 	set_spread(45);
 	set_flatness(0);
 	set_param(PARAM_INITIAL_LINEAR_VELOCITY, 1);
+	set_param(PARAM_ANGULAR_VELOCITY, 0);
 	set_param(PARAM_ORBIT_VELOCITY, 0);
 	set_param(PARAM_LINEAR_ACCEL, 0);
 	set_param(PARAM_RADIAL_ACCEL, 0);

scene/resources/particles_material.cpp

@@ -1202,6 +1202,7 @@ ParticlesMaterial::ParticlesMaterial() :
 	set_spread(45);
 	set_flatness(0);
 	set_param(PARAM_INITIAL_LINEAR_VELOCITY, 0);
+	set_param(PARAM_ANGULAR_VELOCITY, 0);
 	set_param(PARAM_ORBIT_VELOCITY, 0);
 	set_param(PARAM_LINEAR_ACCEL, 0);
 	set_param(PARAM_RADIAL_ACCEL, 0);