Use half float precision buffer for 3D when HDR2D is enabled

This is necessary for Environment effects like Glow to work correctly.

servers/rendering/renderer_rd/shaders/forward_clustered/scene_forward_clustered_inc.glsl

@@ -142,6 +142,8 @@ float sc_luminance_multiplier() {
 	return 1.0;
 }
 
+#define REFLECTION_MULTIPLIER 1.0
+
 #define SDFGI_MAX_CASCADES 8
 
 /* Set 0: Base Pass (never changes) */