- removed array length() function from shadowmap shader

Array's length() function is not yet supported by SPIRV-cross and MoltenVK
Its usage was replaced by explicit nodes count value passed as uniform

src/rendering/hwrenderer/postprocessing/hw_postprocess.cpp

@@ -845,6 +845,7 @@ void PPShadowMap::Update(PPRenderState *renderstate)
 {
 	ShadowMapUniforms uniforms;
 	uniforms.ShadowmapQuality = (float)gl_shadowmap_quality;
+	uniforms.NodesCount = screen->mShadowMap.NodesCount();
 
 	renderstate->PushGroup("shadowmap");