Lower the default directional shadow maximum distance to 100

With the default camera node settings, this makes directional shadows
look consistent between the editor and the running project.

The original issue occurs because the editor camera defaults to a
Z-far value of 500, whereas the Camera node defaults to a Z-far
value of 100. Since the directional shadow maximum distance is clamped
to the Z-far value, it caused the running project's effective shadow
distance to be lower compared to the editor (100 instead of 200).

This partially addresses #13575.

scene/3d/light.cpp

@@ -413,7 +413,7 @@ DirectionalLight::DirectionalLight() :
 
 	set_param(PARAM_SHADOW_NORMAL_BIAS, 0.8);
 	set_param(PARAM_SHADOW_BIAS, 0.1);
-	set_param(PARAM_SHADOW_MAX_DISTANCE, 200);
+	set_param(PARAM_SHADOW_MAX_DISTANCE, 100);
 	set_param(PARAM_SHADOW_BIAS_SPLIT_SCALE, 0.25);
 	set_shadow_mode(SHADOW_PARALLEL_4_SPLITS);
 	set_shadow_depth_range(SHADOW_DEPTH_RANGE_STABLE);