protect the "no ks" flag api action with api access control
add ALWAYS_ALLOWED_ACTIONS only when always_allowed_permission_names was not specified explicitly
call parent validateApiAccessControl instead of Partner::validateApiAccessControl
added strict errors mapping
changed error map implementation after code review
Merge pull request #1486 from kaltura/IX-9.20.0-P-264006

protect flag api with access control, strict error mapping (P-264006)