Fix canvas_item light alpha output in visual shaders

scene/resources/visual_shader.cpp

@@ -1890,7 +1890,7 @@ const VisualShaderNodeOutput::Port VisualShaderNodeOutput::ports[] = {
 	{ Shader::MODE_CANVAS_ITEM, VisualShader::TYPE_FRAGMENT, VisualShaderNode::PORT_TYPE_SCALAR, "normalmap_depth", "NORMALMAP_DEPTH" },
 	// Canvas Item, Light
 	{ Shader::MODE_CANVAS_ITEM, VisualShader::TYPE_LIGHT, VisualShaderNode::PORT_TYPE_VECTOR, "light", "LIGHT.rgb" },
-	{ Shader::MODE_CANVAS_ITEM, VisualShader::TYPE_LIGHT, VisualShaderNode::PORT_TYPE_SCALAR, "light_alpha", "LIGHT.rgb" },
+	{ Shader::MODE_CANVAS_ITEM, VisualShader::TYPE_LIGHT, VisualShaderNode::PORT_TYPE_SCALAR, "light_alpha", "LIGHT.a" },
 	// Particles, Vertex
 	{ Shader::MODE_PARTICLES, VisualShader::TYPE_VERTEX, VisualShaderNode::PORT_TYPE_VECTOR, "color", "COLOR.rgb" },
 	{ Shader::MODE_PARTICLES, VisualShader::TYPE_VERTEX, VisualShaderNode::PORT_TYPE_SCALAR, "alpha", "COLOR.a" },