Fix T63729 Eevee: Bump does not follow normal direction

Referenced by issue #63729, Bump in Eevee does not follow normal direction

source/blender/gpu/shaders/gpu_shader_material.glsl

@@ -3376,7 +3376,7 @@ void node_bump(
     float strength, float dist, float height, vec3 N, vec3 surf_pos, float invert, out vec3 result)
 {
   N = mat3(ViewMatrix) * normalize(N);
-  dist *= invert;
+  dist *= gl_FrontFacing ? invert : -invert;
 
   vec3 dPdx = dFdx(surf_pos);
   vec3 dPdy = dFdy(surf_pos);