Fix max FPS initialization

[mrsaturnsan]

Max FPS needs to be initially set after the DisplayServer is created. Otherwise the Renderer will not get the max FPS value propagated to it.

[clayjohn]

Looks good to me. I think this is a safe change because max_fps is only ever read in two places:

1. The main loop (which doesn't start until well after this)
2. The initialization of the Vulkan RDD

With this change we don't need to grab the max_fps from engine when initializing Vulkan because we can trust that it will be updated later.

Accordingly, we could remove the calculation of max_fps and max_time here:

godot/drivers/vulkan/rendering_device_driver_vulkan.cpp

Lines 3035 to 3036 in cb411fa

	const double max_fps = Engine::get_singleton()->get_max_fps();
	const uint64_t max_time = max_fps > 0 ? uint64_t((1000.0 * 1000.0 * 1000.0) / max_fps) : 0;

And just set the swap interval to swap_chain->refresh_duration

[mrsaturnsan]

Added the requested change :)

[clayjohn]

Looks great to me! The commits just need to be squashed

[mrsaturnsan]

Squashed! :)

[clayjohn]

Looks good to me!

[Repiteo]

Thanks! Congratulations on your first contribution! 🎉