- 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/gl/renderer/gl_renderer.cpp

@@ -195,6 +195,7 @@ void FGLRenderer::UpdateShadowMap()
 
 		mShadowMapShader->Bind();
 		mShadowMapShader->Uniforms->ShadowmapQuality = gl_shadowmap_quality;
+		mShadowMapShader->Uniforms->NodesCount = screen->mShadowMap.NodesCount();
 		mShadowMapShader->Uniforms.Set();
 
 		glViewport(0, 0, gl_shadowmap_quality, 1024);