GPU: Avoid blit operation modifying the wrong framebuffer during restore

At the end of `GPU_framebuffer_blit` when `prev_fb->bind(true);` is called,
the `context_->active_fb` was not in sync and lead to the wrong framebuffer
being modified by bind function.

This fix T81055 SSS light is missing from the diffuse light render pass

source/blender/gpu/opengl/gl_framebuffer.cc

@@ -489,6 +489,8 @@ void GLFrameBuffer::blit_to(
     /* Restore the draw buffers. */
     glDrawBuffers(ARRAY_SIZE(dst->gl_attachments_), dst->gl_attachments_);
   }
+  /* Ensure previous buffer is restored. */
+  context_->active_fb = dst;
 }
 
 /** \} */