Fix compositor backdrop not updating for image invert operator

How to reproduce:
- Have image editor and GPU compositor backdrop enabled and showing the same image
- In image editor, apply inver image colors operator
- Notice how image editor gets updated but compositor backdrop doesn't

Fixes backdrop updates for GPU compositor for the following operators:
- Image -> Invert -> Invert image colors
- Image -> Invert -> Invert red channel
- Image -> Invert -> Invert green channel
- Image -> Invert -> Invert blue channel
- Image -> Invert -> Invert alpha channel

Pull Request: https://projects.blender.org/blender/blender/pulls/119820

source/blender/editors/space_image/image_ops.cc

@@ -3122,6 +3122,8 @@ static int image_invert_exec(bContext *C, wmOperator *op)
 
   BKE_image_partial_update_mark_full_update(ima);
 
+  DEG_id_tag_update(&ima->id, ID_RECALC_EDITORS);
+
   WM_event_add_notifier(C, NC_IMAGE | NA_EDITED, ima);
 
   BKE_image_release_ibuf(ima, ibuf, nullptr);