Merge pull request #107238 from dsnopek/opengl-shadow-to-opacity-plus-unshaded

OpenGL: Fix shader compilation failure with `shadow_to_opacity` and `unshaded`

Author: Repiteo

drivers/gles3/shaders/scene.glsl

@@ -2273,7 +2273,11 @@ void main() {
 
 #if defined(USE_SHADOW_TO_OPACITY)
 #ifndef MODE_RENDER_DEPTH
+#ifndef MODE_UNSHADED
 	alpha = min(alpha, clamp(length(ambient_light), 0.0, 1.0));
+#else
+	alpha = 0.0;
+#endif
 
 #if defined(ALPHA_SCISSOR_USED)
 #ifdef RENDER_MATERIAL