Cleanup: remove redundant headers in source/blender/editors/

Remove redundant headers using
`./source/tools/utils_maintenance/code_clean.py`

Reviewed By: jmonteath

Ref D10364

source/blender/editors/space_sequencer/sequencer_ops.c

@@ -29,12 +29,7 @@
 #include "WM_api.h"
 #include "WM_types.h"
 
-#include "ED_markers.h"
-#include "ED_select_utils.h"
 #include "ED_sequencer.h"
-#include "ED_transform.h" /* Transform keymap. */
-
-#include "SEQ_sequencer.h"
 
 #include "sequencer_intern.h"