Turn off physics and 3d navigation servers in the Project Manager.

[ibrahn]

Copying the editor behaviour of deactivating these servers we're not
using, to reduce CPU load.

Partial fix for #54291

[Calinou]

See also #38208.

Out of curiosity, why can't NavigationServer2D be disabled? I don't see a set_active() method for it, unlike NavigationServer3D.

[ibrahn]

Editor lines, just for easy reference:

godot/editor/editor_node.cpp

Lines 5782 to 5788 in 6b0b1a4

	NavigationServer3D::get_singleton()->set_active(false); // no nav by default if editor
	PhysicsServer3D::get_singleton()->set_active(false); // no physics by default if editor
	PhysicsServer2D::get_singleton()->set_active(false); // no physics by default if editor
	ScriptServer::set_scripting_enabled(false); // no scripting by default if editor

[ibrahn]

I wondered about the Nav2D server as well, but I couldn't find any cases where we deactivate that one, or how to do it, so it may be a more involved puzzle. Neither of the Nav servers seemed to be much of a factor in the CPU usage though so it might not be much of a priority here.

[akien-mga]

Thanks!

[akien-mga]

Cherry-picked for 3.5.