remove outdated API flag from features.md (#10615)

Author: paulOsinski

docs/content/en/usage/features.md

@@ -388,8 +388,6 @@ details about the deduplication process : switch
 
 ### Deduplication - APIv2 parameters
 
-- `skip_duplicates`: if true, duplicates are not
-    inserted at all
 - `close_old_findings` : if true, findings that are not
     duplicates and that were in the previous scan of the same type
     (example ZAP) for the same engagement (or product in case of