Blender Git Loki

Make keyframe inserts/removals less verbose when called from python.

Following operators now only report messages back when they are called via their invoke-methods:

- ANIM_OT_keyframe_insert
- ANIM_OT_keyframe_insert_by_name
- ANIM_OT_keyframe_insert_menu
- ANIM_OT_keyframe_delete
- ANIM_OT_keyframe_clear_v3d
- ANIM_OT_keyframe_delete_v3d

Also removed the attribute confirm_success from the following operators:

- ANIM_OT_keyframe_insert
- ANIM_OT_keyframe_insert_by_name
- ANIM_OT_keyframe_insert_menu
- ANIM_OT_keyframe_delete
- ANIM_OT_keyframe_delete_by_name

Note: addons/scripts possibly need to be updated if they use the above operators AND set the "confirm_success" attribute

Reviewed By: campbellbarton

Differential Revision: https://developer.blender.org/D12697