tentacle: qa/rgw/multisite: remove duplicate test_suspended_delete_marker_incremental...

tentacle: qa/rgw/multisite: remove duplicate test_suspended_delete_marker_incremental_sync

PR #67318 (boto3 migration) cherry-picked onto tentacle conflicted with
PR #66168 which had added test_suspended_delete_marker_incremental_sync
using the old boto API. The conflict resolution added the boto3-rewritten
version of the function but left the original old-API version in place,
resulting in dup definitions with the same name.

Remove the stale old-API duplicate; keep the boto3 version added by PR #67318.

Fixes: https://tracker.ceph.com/issues/76505
Signed-off-by: Oguzhan Ozmen <oozmen@bloomberg.net>